  PREFACE.The following pages have been written with a view to render some aid in establishing a sound and firm basis for future research, on that absorbing topic, the Causes and Nature of Epidemic Diseases. The amount of information already published on Fevers, on the Exanthemata, and on the Plague, is truly astonishing, and the more so when it is considered, that at present no rational account or explanation is given of the causes of these affections. It appears to me but reasonable to suppose that as every thing on this earth has been created on a wise and unerring principle, Epidemic and Infectious Diseases are only indicative of some serious errors in our social arrangements and habits. The dangers and misery brought upon us by disease, may, as shewn by Dr. Spurzheim and Mr. Combe, be warnings against the infringement of the natural laws. Indeed, what is more rational than to suppose that the Seeds of Disease are coeval with the fall of man. His first disobedience No less certain, though after a different manner, are the consequences of minor forms of disobedience. It is so ordained, that certain diseases shall arise, under peculiar conditions, which may have been brought about by a train of causes, easily imagined, and difficult to be explained, but all having their origin in the vices and errors of man in his moral and social relations. If man neglects the cultivation of the ground; with rank vegetation, the germs of fever will invisibly grow and multiply; if he harbours that which is rotten and corrupt, he is himself consumed by those agents destined to remove the rottenness and corruption; it is a part of the law of nature that there should be active and energetic agents for this purpose. The seeds of disease, like the seeds of plants, may be shewn to have His wants and necessities, his sufferings and privations, are the basis of the intellectual progress of man. The wonders of Omnipotence are revealed through the whirlwind, the storm, the pestilence, and the famine. The constructive and perceptive faculties of man have been developed by the necessity of protecting himself from injury by winds and rains; his intellectual faculties have been cultivated, by the sufferings of disease having led him to the study of Famine and distress have aroused his emotions, and softened down his asperities, so that what appears at first to be the infliction of a Curse without Pity, is in reality a Judgment with Mercy. It occurred to me, that on the formation of the Epidemiological Society, the first question for consideration should be, What is the nature of those agents, which induce Epidemic Diseases? are they composed of animate or inanimate matter? In other words, do the manifestations of these diseases exhibit the operations of living or of chemical forces. Having, in my study, dwelt on the subject with an earnest desire to find the truth, I put the suggestion, with my ideas, before the public to reject or receive them. If they be rejected, I can but think a full discussion of the enquiry will lead to the most important results. If they be received with favour, I doubt not others, with more ability, will take up the strain and resolve the discords into harmony. J. G. Wandsworth, September, 1850. CONTENTS.
INTRODUCTION.It is one thing for a man to convince himself, but a very different thing to be able to convince others. I am not now speaking of a conviction arising from the impression made by a few startling facts, nor of one forced on the mind by early prejudices, or by the dogmas of the schools, but of a conviction arising from careful enquiry. In the course of that enquiry, the collector of facts, sees their relations to the idea in his mind, in a multiplicity of ways, from their remaining, each, as one succeeds the other, an appreciable time on the sensorium, and undergoing a certain process of comparison and relation, with all other facts and ideas which have been previously stored up. As the materials for an edifice which have been shaped and prepared in accordance with the completion of the design, so do the facts and ideas which are accumulated The process of thought in the minds of the architect, and in the framer of a proposition, is never exactly the same as in those who contemplate and examine their completed works. Much may be done, however, by both to aid others in comprehending them. The more accurately they keep in view the course their minds have taken, the more readily will their descriptions be understood. To simplify the elements of our knowledge is to give others a ready access to our thoughts. To arrange the course of our ideas in harmony with the elements of our knowledge should be the end of all writing, as it is the only means of multiplying knowledge. It is not the mere accumulation of facts which constitutes science, any more than a collection of building materials constitutes a house, it is the arrangement and adaptation of the means to the end by which the house becomes built and science cultivated. These reflections have been suggested by the circumstance that for the last 3000 years and upwards, Pestilences have at certain intervals done their work of destruction, and opened the springs of misery to untold millions, and yet I see not that we are much further advanced as to the knowledge of the cause of these inflictions than the Jews in the time of Moses. In the Levitical law, as I shall have occasion more particularly to shew hereafter, were directions specially given in reference to the plague of leprosy; what means should be adopted for the cure of the disease, and for preventing its extension, and moreover pointing very significantly to certain facts having connexion with the cause of the affection. Since that time historians generally, and medical writers in particular, have diligently recorded their observations and accumulated facts, on the various desolating plagues which Satisfied in my own mind that the whole subject is beyond the labour of one man, and impressed with the belief that the basis of the enquiry is in anything but a satisfactory state, I have applied myself entirely to the study of the groundwork only, as the primary proceeding for a solid superstructure. The days are past, when imaginary spirits, ethers, and astronomical phenomena, were believed to have any essential influence over our destinies in a physical point of view; we have therefore to deal with matter in some form or other. The question, therefore, which I have proposed for enquiry, is, whether the matter which causes epidemic and endemic diseases, exhibits the properties of inorganic or organized matter. The properties and qualities of organized Having made these preliminary remarks, I have suggested a certain mode of procedure in making enquiries of this kind, not perhaps in strict accordance with logical systems, but on the principle of nature's operations in our own minds, which appears to me, when reduced to a systematic and simple form, to be sufficiently clear and strict for synthetical application, and so concise as to be usefully and practicably applied. In endeavouring to establish a theory for the explanation of extraordinary phenomena, there are certain rules which should guide us in the thorny and treacherous path of speculation. But these rules readily flow from the train of thought, and if we examine our own minds during their operations, we We first commence with an idea, which exists in our minds in the form of a proposition: then the following rules naturally suggest themselves:— 1. The probability of the value of our proposition from inference. 2. The number and value of facts to support the proposition. 3. The reasonableness of the application of the facts to the inference. 4. What amount of information in the form of results can be produced in proof of the tenableness of the proposition.[1] In illustration of the value of these rules the history of Dr. Jenner's discovery affords an appropriate example. To use the words of Dr. Gregory, "he appears very early in The popular notion of the peasantry originated the idea in Jenner's mind, and it became fixed there as a proposition. 1. He commenced his enquiry by observing that the hands of milkers on the dairy farms were subject to an eruption, and he inferred that the notion of the peasantry bore the stamp of probability, which strengthened the idea in his mind and gave force to the proposition. 2. His next step was to accumulate facts; he found on enquiry that the persons engaged on these farms in milking, possessed an immunity from Small Pox to an extent sufficient to strengthen the value of his proposition. 3. The reasonableness of the application of the facts to the inference is clear from the coincidence that the eruption on the hands of the dairy people bore a striking 4. We have but to take the almost universal adoption of vaccination, and its acknowledged prophylactic powers against the propagation of Small Pox to shew the application of our fourth rule.[2] Between the conception of the idea and the accomplishment of Jenner's designs, vaccination seems to have undergone an incubation of nearly twenty years. During that period, with an energy and perseverance only to be obtained by confidence, did this great man brood over and elaborate his idea; and well might the 14th day of May, In adopting the above method I have endeavoured to bear in mind M. Quetelet's observations on the requirements necessary for medical authorship; he says, "All reasonable men will, I think, agree on this point, that we must inform ourselves by observation, collect well-recorded facts, render them rigorously comparable, before seeking to discuss them with a view of declaring their relations, and methodically proceeding to the appreciation of causes." CHAPTER I.IS IT PROBABLE THAT EPIDEMIC, ENDEMIC, AND INFECTIOUS DISEASES, DEPEND UPON VITAL GERMS FOR THEIR MANIFESTATIONS? It is, I believe, almost universally considered that Epidemic, Endemic, and Infectious diseases, originate from some imaginary poisons of a specific nature, each disease having its own peculiar poison. That this conception should have taken possession of the minds of men, is most natural from the symptoms which characterize these diseases, but when we come to enquire into the nature of these agents, or supposed poisons, we are at once struck with the idea that they exhibit one peculiarity which separates them in a marked manner, from those poisons with which we are familiar; for the poisons of Small Pox, Measles, Scarlet Fever, Hooping Cough, Fever, &c. possess the power of multiplication, or spontaneous increase, a property which attaches only to the organic kingdom, and is never known in the inorganic kingdom. The source of most of the poisons is to be found among mineral or vegetable products. A mineral in combination with an acid or oxygen may become a poison, and We are, therefore, constrained to admit that this feature, which distinguishes poisons, is one well worthy attentive consideration. The varieties of poisons may be classified into those which act topically as escharotic poisons, those which act chemically on the blood, and those whose effects are manifested in inducing a speedy annihilation of organic or vital action, as in the case of hydrocyanic acid, which is supposed specifically to affect the nervous centres from which originate the vital manifestations. It is rather remarkable that the vital poisons (as I will call them for distinction), seem to have their appropriate locality in the blood, they do not primarily affect one organ more than another, all the effects we witness resulting from them are to be traced progressively from the blood to other parts of the body. When a person is inoculated with small pox, a very minute portion (indeed it is impossible to say how minute it may be) is sufficient, when absorbed, to excite a certain train of symptoms, all due to absorption of the materies of the disease, and the process by which I here may repeat that among all the poisons known, constituted as they are of various combinations of elementary matter, they are without exception destitute of the power of development or increase. Now, it is pretty accurately known what amount of these poisons is necessary to produce their effects on the living body; we can say how many drops are sufficient of hydrocyanic acid of Scheeles strength, to destroy a man instantaneously. Again, how many grains of arsenious acid are sufficient to induce such an inflammatory condition of the stomach and intestine as will end in death, and how many grains of morphia, will bring about a fatal coma,—but who shall say the amount of the vital poisons necessary to produce their results? It far exceeds the limit of conjecture, to what extent the dilution of miasmatic or contagious matter may be carried, and the poison yet be capable of committing in a short time the most frightful ravages. We may fairly then infer, that if a quantity of matter inappreciable in amount be sufficient to exhibit the characters of growth and increase, that it is endowed with the properties of vitality. That the poisons of scarlet fever, of measles, and of small-pox have this power of growth and increase, is as much a matter of universal belief as that "the sun This power of individual increase, or reproduction, is the very summit of vital manifestation; indeed Coleridge, in his Theory of Life, (in which he says, "I define life as the principle of individuation, or the power which unites a given all into a whole that is presupposed by all its parts,") places reproduction in the first rank, and expresses his hypothesis thus: "the constituent forces of life in the human living body are, first, the power of length or reproduction; 2nd, the power of surface, or irritability; 3rd, the power of depth, or sensibility—life itself is neither of these separately, but the copula of all three." Extensive research is not required to shew that many thinking men believe in the existence of living organic beings, as the elements of contagious and epidemic diseases; the idea indeed seems to flow spontaneously in that direction. Whenever thought, and enduring contemplation, have been concentrated on the subject, the result appears to have been the same, a firm conviction in each individual mind that a vital force must be in operation; or as Schlegel would define it, "a living reproductive power, capable of and designed to develope and propagate itself."—"Its Maker originally fixed and assigned to it the end towards which all its efforts were ultimately to be directed." Referring further to beings having the property of reproduction and propagation, he says, (using When Schlegel wrote this, how little could he have imagined the intricacy of this proceeding among the lower forms of vegetation. It has been shewn by Suminski, and verified by many others, that the mode of impregnation, and the period at which it occurs in the ferns, do not at all correspond to the general notion on this subject. He has discovered in the early development of the frond of ferns certain cells, which he denominates antheridia, or sperm cells; these contain in their cavity a number of subordinate cells, each containing a spermatazoon. At a certain period of the progress of the frond, the parent cells become ruptured and liberate the spermatoza, these move about in a mucilaginous fluid, which bedews the inferior surface of the frond, and become the means of impregnating the germ cells, or pistillidia, with which they readily come in contact. Thus the process of impregnation in these plants occurs during the germination, or what corresponds to the period of germination in the seeds of exogenous and endogenous plants. I have referred to the discovery of Suminski in I will make but two more quotations on the supposed vital character of the germs of disease. "That the air and atmosphere of our globe is in the highest degree full of life, I may, I think, take here for granted, and generally admitted. It is, however, of a mixed kind and quality, combining the refreshing breath of spring with the parching simooms of the desert, and where the healthy odours fluctuate in chaotic struggle with the most deadly vapours. What else in general is the wide-spread and spreading pestilence, but a living propagation of foulness, corruption, and death? Are not many poisons, especially animal poisons, in a true sense, living forces?"—Schlegel.[3] It were useless to multiply quotations to shew And this expression, the seeds, is an universal expression, it is a "Household Word" in connexion with disease. That it has obtained this position in the popular vocabulary is alone a proof of the applicability of the term to the thing intended to be The popular notions found among savage tribes as to the efficacy of certain remedies in the cure of disease have been the means of furnishing us with some of our most valuable medicines, indeed it is almost impossible to say whether originally man did not derive his remedies from the herbs and trees by an instinctive faculty impelling him, as it does the animals when in a state of liberty and with freedom of range, to seek certain plants as they avoid others. It is well known that animals when indisposed will find out some spot as if almost led to it by a visionary guide where the "healing plant" is to be discovered. I am told that sheep have this faculty, and that they will, when affected with the rot, feed upon some plant when they can discover it, which eradicates the disease. Almost every one is familiar with the fact that cats and dogs will crop herbage and eat it; I have A close observer of diseased animals might obtain some useful information by noticing the plants cropped by them while in that condition. The observations should be made in a variety of districts in consequence of the uncertain distribution of some even of the most commonly scattered plants; in one year they may be abundant, but in another they may be almost entirely absent from the same spot.[5] Were it only on the fact of reproduction, I would be contented to take my stand that the force of life is the indwelling power of pestilential matter. Reproduction is a law of nature, and the law of nature is the law of God. And where do we find He prevaricates with us? The more we study His laws the more harmony and perfection we find; what is seeming confusion in the ignorance of to-day, is order in the knowledge of to-morrow. If any one ignorant of the law which regulates the diffusion of gases were CHAPTER II.THE NUMBER AND VALUE OF FACTS TO SUPPORT THE PROPOSITION. ———— SECTION I. ON REPRODUCTION. It is inferred that the proposition, "the matter which operates in the production of Epidemic, Endemic, and Infectious Diseases, possesses the property of vitality," we proceed now to the enumeration of those facts which further elucidate this subject. The facts must necessarily be such as illustrate the identity of properties in the imaginary germs, that are known to exist in demonstrable germs: we take therefore the law of reproduction to be to life, what the law of attraction is to gravitation.[6] But further; do those matters which engender disease furnish to our minds the properties inseparable from life in the abstract? Though the faculty of reproduction is essentially an evidence that the thing which reproduces its kind must be a living body, yet it is only a property or power of living beings and is not itself life, it therefore is necessary to establish the fact that the materies morbi not only has the power of reproduction, but also those properties which in the abstract will prove as far as demonstration can go, that it has the essential properties common to all living bodies. I must again quote from Coleridge, he says: "By life I every where mean the true idea of life, or that most general form under which life manifests itself to us, which includes all its other forms. This I have stated to be the tendency to individuation and the degrees or intensities of life, to consist in the progressive realization of this tendency. The The tendency to individuation cannot be more strongly marked than in the simple experiment of vaccination: we insert a small particle of the so-called vaccine lymph under the skin, and by this means we multiply to an enormous extent, the power which, in the first instance, we had in the form of minute corpuscles in a dry and apparently inert state; nevertheless, though in this condition there must have existed the tendency to individuation or multiplication of individual existence, and the germs are here to their active existence, as seen in the development of the vaccine vesicle, what the egg is to the bird,[7] as described above; we may, therefore, say that the power which exhibits itself in the production of a vaccine vesicle, must have been latent in the dried matter. It is the opinion of Muller that the entire vital principle of the egg After speaking of inanimate objects, Dr. Carpenter says; "and what compared with the permanence of these is the duration of any structure subject to the conditions of vitality? To be born, to grow, to arrive at maturity, to decline, to die, to decay, is the sum of the history of every being that lives; from man, in the pomp of royalty, or the pride of philosophy, to the gay and thoughtless insect that glitters for a few hours in the sunbeam and is seen no more; from the stately oak, the monarch of the forest through successive centuries, to the humble fungus which shoots forth and withers in a day." To be born, signifies the faculty of reproduction existing or having existed in an antecedent being to that one born, and also that itself possesses equally a like power. To be born, is the first expression which must be used in speaking of the faculties or properties of living beings as independent existences, the annual formation of buds, trees, and shrubs, is a multiplication of the species; the coral Now, whether we apply the philosophical language of Coleridge, or the language of observation of Muller, in confirmation of the doctrine here inculcated, we arrive at the same point. Do we not witness in the newly formed vaccine vesicle, an increase of the specific force and principle? We certainly have acquired by the process of vaccination a manifold multiplication of power, and is there not also assimilation of new matter in "We revert again to potentiated length in the power of magnetism (reproduction); to surface in the power of electricity, and to the synthesis of both or potentiated depth in constructive, that is chemical affinity."[9] Some may be at a loss to conceive, at first, how irritability may be considered a property of all vegetable matter; that it does exist in some vegetables is certain, but that it does exist in all living beings is equally certain;[10] the term, however, which would appear more appropriate when that irritability does not exhibit itself in an appreciable form, is impressibility. Irritability, as commonly understood, is seen in its highest condition in muscular tissue; but "the irritable power and an analogon of voluntary motion first dawn on us in the vegetable world in the stamina and anthers at the period of The property of irritability attains its acme in man, the most highly organized of all beings; and its gradations pass downwards through the whole scale of animate creation; not so reproduction, for this faculty observes the very opposite direction, for in plants a single impregnation is sufficient for the evolution of myriads of detached lives. Reproduction is a fact, it is an essential property of life, and is a reality to us from observation; but irritability is not so tangible and demonstrable a property. We nevertheless may assume its universality, from the circumstance that we lose sight of it by imperceptible degrees; the irritability of the sensitive plant is as much irritability as that of the highly organized muscle; but because the faculty evades our perception, "in tapering by degrees, becoming beautifully less," we have no reason for pronouncing its total extinction at any one point of the vegetable kingdom,[11] any more than we should have I think we are now in a condition to assume, as far as abstraction will conduct us without proceeding to an extreme length, that the materies morbi, or, as I will now call them for the sake of clearer distinction, semina morbi, possess those properties which in the abstract are common to all living beings. Another argument strikes me as capable of adding further strength to the proposition. We need but be told that a small piece of iron was placed in a certain position with regard to another piece of iron, and that the smaller piece moved through a given space and became attached to the larger, to infer that magnetic force was in operation. Supposing this magnet then to be folded in paper, and that it The nebular theory, from which some astronomers made the foundation of many speculations, came with so much interest to our minds that the fascination could not be resisted. It was most delightful to revel in the imagination that we possessed a key to the mode of formation of the starry hosts, and when speculation had taken its extreme limits in the "Vestiges of the Natural History of Creation," and the nebulÆ had served as the ground work of a gigantic scheme, Lord Ross's monster telescope swept the heavens of its cobwebs. We can imagine this great promoter of science saying to us, Gentlemen, the clouds which have obscured you, are composed of myriads of stars, and comprise systems as vast and as luminous as our own, had you but power of vision to discern them. A new light thus appeared to philosophers, and though no great practical results may flow from the discovery, it is instructive from the fact that the imperfectly aided or unaided vision, should not limit legitimate Should these observations made by Mr. Spooner turn out to be correct, they will but fulfil my anticipations. Then again shall we see the same application of imperfect vision to the limitation or temporary obstruction of solid and determinate knowledge. We may reasonably expect that these bodies, discovered by Mr. Spooner, should be the elementary matters of disease. Their existence was predicted from the probability that living matter must be the agent; moreover, that this matter when discovered It was predicted that a planet would be discovered in a certain position in the heavens, because the perturbations of a comet indicated an attracting body in the path of the eccentric wanderer; the prediction and the fulfilment were almost simultaneous. SECTION II. HISTORICAL NOTICE OF EPIDEMIC DISEASES. The earliest notices we have of Pestilences are contained in Holy Writ. The plagues which smote the Egyptians in the time of Moses are not unworthy some comment here. Of those ten plagues, four out of the number were due to the miraculous appearance of myriads of the lower animal tribes, in three instances of insects,[13] viz. lice, flies, and locusts; in the fourth, when Aaron stretched forth his hand with his rod over the streams, over the rivers, and the ponds, frogs came up and covered the land of Egypt. In these instances living beings are made the instruments in God's hand for the punishment of the wicked. These plagues include the second, third, fourth, and eighth. The first plague is mentioned as a conversion of the waters into blood. Now if we may take this expression as being literal, there is no reason to suppose that this blood differed in any respect from ordinary sanguineous liquid; we therefore may assume, as the blood is every where in Scripture spoken of as the life, that this fluid was endowed with vital properties. The fifth plague is described as a murrain among beasts; and the sixth, as exhibiting itself as "a boil breaking forth with blains, upon man and upon beast."[14] Now these affections bear a resemblance to the diseases known to us at the present day through authentic records. The Black Death of the 14th century affords in its history but too awful a picture of the horrors of such pestilences. In the tenth plague, the smiting of the first-born, we are not told by what means it was brought about; but we have something even here to lead us to conjecture. In the second visitation of the Black Death, there were destroyed a great many children whom it had formerly spared, and but few women. The seventh plague of hail is within our conception; as is also that of darkness, the ninth plague. It is not a little remarkable that of the ten plagues, seven of them depended upon agents intelligible to our comprehension; we can conceive of From this abstract we discover that the three plagues whose causes we cannot understand, or rather upon which no light has been thrown by Scripture, bear analogies to those which we recognise, in the writings of modern authors, as fearful pestilences. It is now our province to reflect on the causes supposed to be in operation in the three instances, which become naturally separated from the rest. We are told that a murrain appeared among the cattle, without any preliminary step. When the blains broke out upon man and beast, Moses had been previously directed by the Almighty to take handfuls of the ashes of the furnace, and sprinkle them towards the heaven in the sight of Pharaoh. "And it shall become small dust in all the land of Egypt, and shall be a boil breaking forth with blains upon man and upon beast, throughout all the land of Egypt." Another coincidence, in connexion with subsequent pestilences, arrests the attention, on the subject of the mysterious appearance on these occasions of Hecker, in writing on the Black Death says, the German accounts expressly speak of a "thick stinking mist which advanced from the east,[15] and From 1500 to 1503 in Germany and France, during the prevalence of the sweating sickness, spots of different colours made their appearance, "principally red, but also white, yellow, grey, and black, often in a very short time, on the roofs of houses, on clothes, on the veils and neckerchiefs of women, &c." Blood rain is also mentioned as having occurred at this time, which consisted of the aggregation of minute particles of red matter. In the seven plagues, miraculous operations of the Deity consisted in the unusual manifestation of phenomena, but which in their effects are recognizable as of clear and definite import. The miracles here are,—in the mode of producing the swarms of frogs, locusts, &c. but they are manifest and unmistakeable causes of plague and famine; in the other three, on the contrary, we witness only the effects, the causes are hidden from us; we may, therefore, as in current events, legitimately investigate the subject, and what better course can be adopted than that which classifies the traditionary past with all subsequent history. Presuming such a method of research to be admitted, I have assumed that as Further on in the book of Leviticus are passages which I cannot forbear transcribing, for they point out to us most indubitably a line of enquiry in reference to diseases of a contagious nature. "The garment also that the plague of leprosy is in, whether it be a woollen garment, or a linen garment, whether it be in the warp or woof, of linen or of woollen, whether in a skin, or in any thing made of skin, and if the plague be greenish or reddish in the garment ... it is a plague of leprosy, and shall be shewed unto the Priest, and the Priest shall look upon the plague and shut up it that hath the plague seven days; and he shall look on the plague on the seventh day; if the plague be spread in the garment, either in the warp, &c. ... the plague is a fretting leprosy, it is unclean. He shall therefore burn that garment ... wherein the plague is, for it is a fretting leprosy; it shall be burnt in the fire. And if the Priest shall look, and behold, the plague be not spread in the garment ... then the Priest shall command that they wash the thing wherein the plague is, and he shall shut it up seven days more: and the Priest shall look on the plague, after that it is washed: and behold if the plague have not changed his colour, and the plague be not spread, it is unclean; thou Again in Deuteronomy. The curse for disobedience: "The Lord shall make the pestilence cleave to thee until he have consumed thee from off the land.—The Lord shall smite thee with a consumption, and with a fever, and with an inflammation, and with an extreme burning, and with the drought, and with blasting, and with mildew, and they shall pursue thee until thou perish.—The Lord shall make the rain of thy land powder and dust: from heaven shall it come down upon thee until thou be destroyed." It may be said, and I doubt not will be said, all this is unnecessarily dragging the sacred volume into an enquiry totally foreign to its general tenor; on the contrary, however, I maintain by that Book we are to learn the ways of God to man, and further, that no study can impress mankind with so awful, so terrific an idea of his responsible position, as that which leads him into the investigation of the causes There is no man would less willingly than myself introduce profanely the revelations of Scripture. The observations here made are not, therefore, intended for light or heedless controversy; if they have a significance of any import, let them be alluded to in the same spirit with which they have been quoted; if they convey nothing for approval to the reader, let silence rest upon them. To those who would fain disregard my request, let me recall to their minds the veneration which from childhood I trust we have always felt on hearing or seeing those two words—Holy Bible. It is yet to be determined, whether the greenish or reddish appearance of the garment spoken of, as being contaminated with the plague of the leprosy had any specific relation to the disease itself. The priest orders that the garment shall be shut up seven days, and on the seventh day, if the plague be increased, by which, of course, is meant if the greenish or reddish colour have increased, and from which we may gather that a power of spontaneous increase was possessed by the matter, such a result indicated a fretting leprosy, and the garment was to be burnt. Again, though there may have been no increase, but a persistence of the coloured matter after shutting up and washing the garment, it is to The facts above noticed, accurately correspond to what we now know as applicable to the matter of infectious and contagious maladies. It is a rule, I believe universally adopted throughout the Poor-houses of this country, to put the clothes of all persons about to become residents in these establishments, into ovens, where they are submitted to a temperature incompatible with the existence of either animal or vegetable life. By this means all living matters are destroyed, but the fabrics and inorganic matters retain their properties intact. This simple proceeding, I am credibly informed, is an effectual preventive of contamination by articles of clothing, a desideratum of no small importance, when it is A few more observations are called for on the quotation from Deuteronomy, in which allusion is made to living matter being an agent in the production of disease. In the curse upon the children of Israel for disobedience, we read that they are to be smitten with mildew. No further information, however, is vouchsafed to us, nevertheless, we can conceive the wretched condition of those on whom the curse might fall. Again, we find in a continuation of this curse that the Almighty uses means such as He adopted in the sixth plague of the Egyptians. The ashes of the furnace became a small dust in all the land of Egypt, breaking forth with blains upon man and beast. In the curse of the Israelites the words are: "The Lord shall make the rain of thy land powder and dust: from Heaven shall it come down upon thee until thou be destroyed." It might be conjectured that the absence of rain would be sufficient to account for the extinction of the people on whom the curse was pronounced, by the famine and drought necessarily attendant upon the loss of moisture. But this does not appear to be the meaning of the passage, for the powder and dust are mentioned as the agents of destruction; besides, in the continuation of the curse, the locust is to destroy the grain, the worm the grapes, and As far then as Sacred History conducts us in the enquiry, concerning the causes of pestilences, we gain encouragement in the belief that living germs are the active agents, for in the case of the leprosy, we have evidence of reproduction in connexion with infection, which, if our line of argument be tenable, amounts to demonstration; then, in the other instances of the plagues, by boils and blains, they distinctly bear comparison with the accounts given by profane writers, of the visitations of pestilences on the earth, subsequently to those mentioned in Scripture history. This leads now to the consideration of recorded facts observed and noted during the various Epidemics in the early and subsequent periods of Man's History, as given by those on whom reliance may be fairly placed. Setting aside the uncertain information contained in the writings of the Chinese,[17] a people whose To say that a disease commenced in the East and travelled westward, and at length found a habitation and a name in every part of the globe, is no more than to say that disease is coeval with the fall of man. The cause is as much hidden in the region of its birth, as in that where it sojourns for a time. The cause of the sweating sickness was as much a mystery in England as in all the other nations of Europe, which were visited by its devastating power. And these observations apply with as much force to one disease as another; for even our indigenous ague, originating in some places so limited that the shadow of a passing cloud may mark the boundary of its dwelling place, as inscrutably evades our vigilance, with all the appliances that art can bring to our assistance, in endeavouring to evoke its extraordinary properties under the cognizance of our senses. If we weigh the air which carries the poison, or analyze it by the most delicate chemical tests, or "These are Thy marvellous works!" and confess our total inability to fathom the unbounded. If then no practical advantage can accrue from investigating the writings of the ancients on these subjects, beyond comparing their historical statements with those of more recent date, our purpose will be served by occasionally embodying any remarkable observations of the former with those of the latter. In proceeding with this course it were better to confine our minds chiefly to two diseases which appear from history to have been known from the earliest periods, these are the Plague and the Small Pox, mentioning other diseases only en route. Passing then, to the sixth century of the Christian era for the first distinct and connected account of the Plague, it appears from a host of testimony, that the history of this disease, as given by Procopius, well merits our attention. Drs. Friend and Hamilton, in their Histories of Medicine, and Gibbon, in his History of Rome, are equally warm in their praise of Procopius: the latter says, he "emulated the skill and diligence of Thucydides in the But some phenomena preceding the outbreak of the pestilence are observed as coincidences by all authors. Gibbon thus writes: "I shall conclude this chapter with the comets, the earthquakes, and the plague which astonished or afflicted the age of Justinian." From the accounts given by this author, earthquakes for some years had been threatening and destroying many portions of the globe, From this short notice of the Plague of 543, I pass to the ninth century, when Rhazes, the Arabian physician, endeavoured to enlighten the world on the subject of Small Pox.[19] In quoting his opinions, I am not to be understood as subscribing to them, but merely endeavouring to point out some peculiar and interesting observations. First, then, Rhazes attributes the disease to a condition of the blood, which he thus describes, to shew how it happens that in infancy and childhood the disease is most prevalent, and that old age is "Now the Small Pox arises when the blood putrifies and ferments, so that the superfluous vapours are thrown out of it, and it is changed from the blood of infants which is like must, into the blood of young men which is like wine perfectly ripened: and the Small Pox itself may be compared to the fermentation and the hissing noise which take place at that time." But the cause of the disease is simply alluded to by this author, as depending upon "occult dispositions in the air," and as he speaks here of Measles with the Small Pox he goes on to say—"which necessarily cause these diseases and predispose bodies to them." This notion of Rhazes that there is some peculiar condition of the blood which favours a process resembling fermentation is not without interest. The circumstance that individuals are not We pass now without further comment to the epidemics of the Middle Ages; and here the work of the philosophical Hecker leaves us little else to desire in the way of information, as far as it is obtainable from published records. From the manner in which he has grouped the facts which presented themselves to his mind in the course of a most laborious research, he has saved the student of this subject much toil in acquiring matter for reflection; he has here but to read and digest. I know not how to select from this invaluable work the most striking passages, to strengthen and support my hypothesis, for not a page is destitute of facts corroborative of the doctrine that vital germs are the material agents of pestilential disorders. The opening paragraph to the Black Death is a most cogent illustration of the assertion; it is, as it were, the theme of the work. "That I must here apologise for large transcripts from Hecker's work, for neither could I command the amount of knowledge there displayed, nor use such appropriate language as the learned translator has employed. It is not doubted that the Black Death was an Oriental plague, only of more than usual severity, and wider spread influence of the infectious nature of this disease, and the active properties of the matter producing it. Hecker says, "articles of this kind—bedding and clothes—removed from the access of air, not only retain the matter of contagion for an indefinite period, but also increase its activity, and engender it like a living being, frightful ill consequences followed for many years after the first fury of the pestilence was past."[21] As extraordinary atmospheric and telluric phenomena preceded the Plague in the time of Justinian, so do we find similar instances recorded as the precursor of a similar visitation 700 years later. I am concerned more with those circumstances which refer more especially to my subject, viz. the development of organic matter, and the peculiar odours of the atmosphere, the latter being evidence of some foreign and unusual production in our respiratory media. "On the island of Cyprus, before the earthquake, a pestiferous wind spread so poisonous an odour, that many being overpowered by it, fell down suddenly and expired in dreadful agonies. A thick stinking mist advanced from the east, and spread itself over Italy." It is probable that the atmosphere contained foreign and sensibly perceptible admixtures to a great extent, which, at least in the lower regions, could not be decomposed or rendered ineffective by separation. In 1348 an unexampled earthquake shook Greece, Italy, and the neighbouring countries. During this earthquake the wine in the casks became turbid, a proof that changes causing a decomposition of the atmosphere had taken place. "The insect tribe was wonderfully called into life, as if animated beings were destined to complete the destruction which astral and telluric powers had began." "The corruption of the atmosphere came from the east, but the disease itself came not upon the wings of the wind, but was only excited and increased by the atmosphere where it had previously existed." "The most powerful of all the springs of the disease was contagion; for in the most distant countries, which had scarcely yet heard the echo of the first concussion, the people fell a sacrifice to organic poison, the untimely offspring of vital energies thrown into violent commotion." "After the cessation of the Black Plague, a greater fecundity in women was every where remarkable, a grand phenomena, which from its occurrence after every destructive pestilence, proves to conviction the prevalence of a higher power in the direction of general organic life." In the article Contagion, of the Essay, Sweating Sickness: "Most fevers which are produced by general causes, propagate themselves for a time spontaneously." "The exhalations of the affected become the germs of a similar decomposition in those bodies which receive them, and produce in these a like attack upon the internal organs, and thus a merely morbid phenomenon of life, shows that it possesses the fundamental property of all life, that of propagating itself in an appropriate soil. On this point there is no doubt, the phenomena which prove it have been observed from time immemorial, in an endless variety of circumstances, but always with a uniform manifestation of a fundamental law." Mead, in his Essay on the Plague, makes many observations of great interest and worthy a physician of eminence; and where, in recent times, shall we look for any more definite information concerning the causes of pestilences? It is not a little singular that at the time this book was published, it was read with such avidity that it went through seven editions in one year.[22] From this circumstance we may gather that the public generally took a lively and proper interest in a subject that was not only of domestic, but national importance. Whether this interest was stimulated by the fact that the work was written expressly by order of the On the spread of the Plague is the following:—"The plague is a real poison, which being bred in the southern parts of the world, maintains itself there by circulating from infected persons to goods, that when the constitution of the air happens to favour infection, it rages with great violence." Contagious matter is lodged in goods of a loose and soft texture, which being packed up, and carried into other countries, let out, when opened, the imprisoned seeds of contagion, and produce the disease whenever the air is disposed to give them force, "otherwise they may be dispersed without any considerable ill effects." Gibbon thus speaks of the above quoted work: "I have read with pleasure Mead's short but elegant Treatise concerning Pestilential Disorders;" many also might read it at the present day with infinite advantage. Mead most satisfactorily combats the opinions of the French physicians who maintained the non-contagiousness of the Plague. Experience proves beyond doubt, that certain conditions of atmosphere, of Dr. Bancroft was of opinion that specific contagions are each and severally creatures of Divine Wisdom, as distinctly and designedly exerted for their production, as it was to create the several species of animals and vegetables around us. The indigenous fever of Ireland, which has several times shewn itself in an epidemic form, appears to have been as fatal, as the Plague in the South of Europe. Its devastations have generally been associated or preceded by famine and general distress. Dr. Harty, writing in 1820, says that thrice within the last eighty years has the same fever appeared in its epidemic character. In the year 1741 Ireland lost 80,000 of her inhabitants from this cause. It is a maculated typhus, and considered to be a special product of the Emerald Isle. It has been shewn that fever began to exceed its ordinary rate in those places first where famine and want of employment were most severely felt,[24] and that in such places and under such circumstances, it was most prevalent and fatal. The physicians generally believed it to have been spontaneously produced and not to have been imported. In the last Famine Fever of Ireland, Liverpool and several other places suffered severely from the The Sweating Sickness prevailed in England alone at first, but at length sought foreign victims. The Cholera is an exotic disease, as well as the Plague, but they occasionally have visited our shores, and their seeds remain among us. The Small Pox is now even not known in some parts of the world, but when once it is established, who can predict the period of its first appearance in an A disease previously unknown in India appeared at Rangoon in the year 1824, which obtained the name of Scarlatina Rheumatica. Four years afterwards it attacked the Southern States of North America, and though the disease was so impartial as scarcely to spare a single individual of any town to which it extended its influence, it was not accompanied with that mortality which has usually been the characteristic of wide spread epidemics. There is one peculiar feature of all epidemics which may be here mentioned as indicative of some definite, though at present unaccountable cause, operating in the sudden suppression of the disease after a certain period of duration. This distinctive character may almost be considered as a law in reference to these affections; if we take three distinct diseases, the Plague, the Irish Fever and the Cholera, we find the rule apply to all. Of the latter disease we have so recently been witnesses, that I need not quote authorities on this point concerning it. In Dr. Patrick Russell's work on the Plague at Aleppo I find the following remarkable passage. After alluding to the great increase of pestilential effluvia that there must be towards the close of an epidemic, compared with the amount at the onset of the disease, and expressing his The expressions of Dr. Harty on this subject, in connexion with the Irish Fever, would apply as well to all other epidemics: "It is a fact, that though every diversity of management was resorted to for effecting the suppression of the disease, yet, nevertheless, there was an almost simultaneous and apparently spontaneous decline of the epidemic in the various and most remote parts of Ireland. It is not an easy matter to offer a satisfactory explanation of this circumstance, some general cause must no doubt have influenced the subsidence of the disease, yet that cause could not be atmospheric, inasmuch as the decline, though it might be said to be simultaneous, was not sufficiently so to admit of that explanation." SECTION III. THE DISPERSION OF PLANTS AND DISEASES. The dispersion of Diseases and the dispersion of Plants, exhibit analogies which might be little expected, on a superficial view of the enquiry. We are led to believe, that the earth as a whole, was not covered with vegetation in a day, the geological history of this planet is one of development, and though at first sight this expression of opinion may appear to savour of doubt in the Mosaic record, a more extended acquaintance with the subject, favours rather and confirms Scripture history. As the peopling of the earth has been a gradual process with the animal creation, so has it been also with the vegetable kingdom. We see at the present day, that plants by various means of transit from place to place, multiply themselves on new soils and in new climes, the same with animals. By other means we observe, or can trace, the extinction from various localities and countries, of members of both the animal and vegetable kingdom. We learn that originally this planet had a temperature much higher than at present, and that the variation of temperature between the equator and the poles, which we now witness, did not obtain in the earlier condition of the globe. We are given to understand, and not without considerable proof, "Where blue mists, through the unmoving atmosphere, Scatter the seeds of pestilence and feed unnatural vegetation." In the new era, when the earth took its present physiognomy, who shall say whether much of the pestiferous matter may not have been enclosed and condensed in the bowels of the earth, and when it is remembered, that earthquakes and convulsions of nature,[25] have invariably preceded the outbreak of After the various commotions which left the globe, with its present physiognomy of mountains, plains, valleys, rivers, lakes, and oceans; a new Flora and Fauna appeared to adorn and animate the scene of man's existence. Plants and animals were created apparently in adaptation to the numerous climes, which the seasons in the various latitudes or the elevations of the soil, were prepared to render fruitful and useful each in its own sphere. Besides this, the plants of the same latitude, in some instances, differ materially from each other; in this case it seems that the soil has much to do with this peculiarity, for it is certain that the soil and the contiguous atmosphere, have a close and intimate relation; the drought of the desert depends upon the sand, as humid atmosphere is connected with the morass. To illustrate the tendency which vegetation shews in appropriating one locality more than another, I may quote the following: "Some of the volcanic masses of the Æolian or Lipari Islands, that have existed beyond the reach of history, are still without a blade of verdure; while others in various parts, of little more than two hundred years date, bear spontaneous vegetation, and the same is seen on two lavas of Etna near each other, for the one In comparing the diffusion of plants, and the diffusion of diseases, the different modes by which this generally has been effected may be considered under heads, that the comparison may be more readily traced. First, seeds are diffused by the atmosphere, either by the prevalence of certain currents, which are produced by known laws, in which case, no difficulty occurs in the explanations; or in a more imperceptible manner, as by those more uncertain atmospheric currents of a partial nature, which, though they seem to have laws governing them, are not yet understood. Second, seeds are transported by water across oceans, &c. when they can be floated on any material by which they are preserved, as by wrecks and masses of wood, which have been washed down the rivers. Third, they are conveyed by man to all parts of the globe. Fourth, a period of latency is observed to apply to them, that is, they require certain essential conditions before germination occurs; so that even in some localities, a plant may not have been known to exist in a particular neighbourhood, but by a train of circumstances, it may make its appearance, and again be a centre of development. 1st. I shall not here wander into the speculation, Many seeds are provided with means adapting them for floating in the atmosphere, these are by pappi, or winglets and hairs, but it cannot be doubted that the agency of atmospheric currents, is productive of considerable effects in the dispersion of lighter seeds, such as those of mosses, fungi, and lichens—lichens have been discovered in Brittany, which are peculiar to Jamaica, and Monsieur De Candolle concludes, that their seeds had been carried thence by the south-westerly winds, which prevail during a great part of the year on this portion of the French coast. But Humboldt's testimony on the subject of winds is most satisfactory, for he says, "Small singing birds, and even butterflies, are found at sea, at great distances from the coast (as I have several times had opportunities of observing in the Pacific), being carried there by the force of the wind, when storms come off the land." It is generally believed, from abundance of proofs, that the trade winds, and other continuous currents, are means by which plants are conveyed from one country to another.[26] As to the partial currents, Humboldt further says, "The heated crust of the earth occasions an ascending vertical current of air by which light bodies are borne upwards. M. Boussingault, and Don Mariano De Rivero, in ascending the summit of the Silla, one of the gneiss mountains of Caraccas, saw in the middle of the day, about noon, whitish shining bodies rise from the valley to the summit of the mountain, 5755 feet high, and then sink down towards the neighbouring sea coast. These movements continued uninterruptedly for the space of an hour. The whitish shining bodies proved to be small agglomerations of straws, or blades of grass, which were recognized by Professor Kunth, for a species of vilfa, a genus, which together with agrostis, is very abundant in the provinces of Caraccas and Cumana." On the plague of locusts we read, that "the Lord brought an east wind upon the land, all that day and all that night, and when it was morning the east wind brought the locusts." On the Black Death we read, "There were many locusts which had been blown into the sea by a hurricane, and a dense and awful fog was seen in the heavens, rising in the east, and descending upon Italy." Of the Plague of 542, Gibbon says, "The winds might diffuse that subtle venom, but unless the atmosphere be previously disposed for its reception, the plague would soon expire in the cold or In the history of the Sweating Sickness, of which there were five distinct visitations, we find ample allusions to the atmosphere, and the mode in which the disease was conveyed by this medium. I quote again from Hecker: "It seemed that the banks of the Severn were the focus of the malady, and that from hence, a true impestation of the atmosphere, was diffused in every direction. Whithersoever the winds wafted the stinking mists, the inhabitants became infested with the sweating sickness. These poisonous clouds of mists were observed moving from place to place, with the disease in their train, affecting one town after another, and morning and evening spreading their nauseating insufferable stench. At greater distances, these clouds being dispersed by the wind, became gradually attenuated yet their dispersion set no bounds to the pestilence, and it was as if they had imparted to the lower strata of the atmosphere, a kind of ferment which went on engendering itself even without the presence of the thick misty vapour, and being received into men's lungs, produced the frightful disease everywhere."[27] Mr. K. B. Martin, harbour-master of Ramsgate, in a communication to Lord Carlisle on the Cholera of last autumn, says, "At midnight of the 31st August (1849), the Samson (steam-tug) proceeded to the Goodwin Sands, where the crew were employed under the Trinity agent, assisting in work carried on there by that corporation. While there, at 3 A.M. 1st September, a hot humid haze, with a bog-like smell, passed over them; and the greater number of the men there employed instantly felt a nausea. They were in two parties. One man at work on the sand was obliged to be carried to the boat; and before they reached the steam vessel at anchor, the cramps and spasm had supervened upon the vomitings; but here they found two of the party on board similarly affected. Here then is a very marked case without any known predisposing local cause. Doubtless it was atmospheric, and in the hot blast of pestilence which passed over them." Many more instances might be quoted, to shew that the germs of disease, as well as of plants, are borne on the wings of the wind from place to place 2nd. The transportation of seeds of plants by water requires very little notice; every one is familiar with the mode in which coral islands, which gradually rise out of the sea, become covered with vegetation. "If new lands are formed, the organic forces are ever ready to cover the naked rock with life.—Lichens form the first covering of the barren The following may be cited as an instance of the transportation of disease by water. "Cyprus lost almost all its inhabitants, and ships without crews were often seen in the Mediterranean, or afterwards in the North Sea, driving about, and spreading the plague wherever they went on shore."[30] It requires no argument to enforce the conviction that cottons, woollens, furs, skins, &c. will retain the matter of infection for almost an indefinite period; instances of the kind have been already given; it is therefore easy to understand that portions of wrecks and ship's goods would be a frequent though unsuspected source of infection. Dr. Halley mentions a case, in which a bale of cotton was put on shore at Bermuda by stealth; it lay above a month without prejudice, where it was hid, but when opened and distributed among the inhabitants, it produced such a contagion that the living scarce sufficed to bury the dead. Dr. Walker found seeds dropt accidentally into the sea in the West Indies cast ashore on the Hebrides. He says, "the sea and rivers waft more seed than sails." The waters of many rivers induce diarrhoea and dysentery.[31] Well water also in many 3rd. The part performed by man himself in the communication of disease to his fellow creatures, is perhaps the most fruitful source of the extensive spread of epidemic and contagious diseases. In the time of Moses, restrictions were laid on those who had the plague of the leprosy to avoid contagion; the dictum for one so affected was, "he shall dwell alone; without the camp shall his habitation be."[32] All the ancient authors believed in the The history of the introduction of Scarlet Fever, Hooping Cough, Lues, and other diseases into the various countries of the globe, is sufficiently convincing that men carry about with them the seeds of disease; that while these attach themselves to the persons and clothing of those who introduce them into new climes, and flourish independently of cultivation, yet the exotics which they foster with so much care, often disappoint their most sanguine expectations; and these "languishing in our In 1846, a large vine, the black Hambro-grape, We are apt to attribute an abundant or scarce fruit season to temperature alone, but this is an error—for we have before remarked, that though certain lands may be in the same degree of latitude, the plants which thrive well on one land, will not do so on the other: in fine, that where reason and analogy would lead one to expect a particular form of vegetation, a totally different Flora is presented to the view. These facts are indeed suggestive of new and important deductions. Is it yet explained why the town of Birmingham should be free from Cholera? There is a large manufacturing population, a great number of poor, the usual overcrowding of individuals in small chambers, a considerable amount of destitution and depravity; irregular habits of living, and unwholesome diet, and doubtless many parts of the town, which on investigation would have yielded all the elements usually considered necessary for the localization of the disease: but no—here was some repelling cause, some opposing agent to the generation and propagation of the pestilential seeds. There are no known laws by which inorganic matter could be supposed to observe such a selection, or such an antagonism. Electricity, magnetism, ozone, gases, exhibit no such elective properties that here they will destroy, and 4th. As to the time of latency, facts crowd upon us indefinitely, as elements of comparison between vegetation generally, and disease in its early stages and history. The seeds of plants are extraordinarily tenacious of life. What a mysterious arrangement of the ultimate particles of matter must there be, by which the vital force remains apparently inactive for many years, and yet when the conditions arise favourable to its manifestation, as it were by an extraordinary fiat, life appears. Previous to the year 1715, no broom grew in the King's Park, at Stirling; but in that year a camp was formed there, and the surface of the ground consequently was broken in many places. Wherever it was broken, broom sprang up. The plant was subsequently destroyed; but in 1745 a similar growth appeared after the ground had been again broken for a like purpose. Some time afterwards the park was ploughed up, and the broom became generally spread over it. "In several places in the neighbourhood of Edinburgh," says Professor Graham, "the breaking of the surface produces an abundant crop of Fumaria parviflora, What limit can there be to the dispersion of seeds when their vital properties may remain so long unimpaired? The seeds of which we have been speaking were, no doubt many of them, washed away with the waters of the Teith, and carried by the stream into the Forth; and who shall then mark their destination; for we have seen that by such means the most distant lands are supplied with vegetation; for whence come the plants which cover the Coral Islands, unless by the air and the water, and that both contribute, has been incontestably proved. Dr. Lindley states that melon seeds have been known to grow when forty-one years old; maize thirty years, rye forty years, the sensitive plant sixty years, kidney-beans a hundred years. But seeds in general have an indefinite period, apparently, at which they can retain their power of germination; for many of the seeds which had been kept in the herbarium of Tournefort for more than a century, were found to have preserved their fertility. It has now to be shewn that the germs of disease also retain their vital powers in a state of dormancy during a lengthened period. Mead has very judiciously observed, "to breed a distemper, and to give force to it when bred, are two different things." He further remarks, that the seeds of the Plague may confine themselves to a house or two during a hard frosty winter, and be preserved, and again put forth their malignant quality as soon as the warmth of the spring gives them force. It is certainly very remarkable that the Plague of London, which commenced at the latter end of the year 1664, should "lie asleep," as Mead says, from Christmas to the middle of February, and then break out in the same parish. It has been also known that an infected bed laid by for seven years had done infinite mischief on being again brought into use. Indeed, it is quite uncertain for how long a period woollen, fur, linen, cotton, and other articles may retain infectious matter in a dormant state. It has been supposed by some that in closely packed bed and body clothes a multiplication of the germs may and does take place, nor do I see any reason why this should not be the case, for these articles contain within their structure the effluvia of the animal body, and they may possibly there find sufficient nutriment for their development. Nees von Esenbeck believed that some of the minute Cryptogamia were re-produced in the air, we are not therefore exceeding philosophical conjecture when we imagine a basis and substratum, though an unusual one, for the germs of vegetation. Exclusion from air and light, Small Pox and Cow Pox matter, which are now proved to be the same virus, the former modified by having been through a process of growth and maturation in the cow, are both remarkable for exhibiting their active properties after having lain dormant for a considerable time. And each, though so closely allied, retaining its specific properties. This peculiarity in the history of Small Pox virus suggests a comparison with some phenomena of vegetation, viz. that of grafting or budding. The lower Cryptogamia in their fructifications resemble rather multiplication by buds than by seeds. M. Moyen's idea is that every spore or little globule, independently of its neighbouring one, lives, absorbs, assimilates, grows, and re-produces on its own account; this is certainly the characteristic of the Torula and the Uredo, and doubtless is so of many other of the Cryptogamia, the Protococcus nivalis is another instance. Other modes of cultivation produce also great varieties of results of an unexpected kind. Would any one, says Dr. Walker, imagine that cabbage, cauliflower, savoy, kale, brocoli, and turnip-rooted cabbage, were the same species? yet nothing is more certain than that they are only varieties produced by the cultivation of the Brassica oleracea, These varieties in vegetables have now become permanent, and though it is supposed that each is liable to return to its original condition, I am not yet certain that such is the tendency. A deterioration is not unlikely to ensue in the course of time, because the propagation by seeds must necessarily very much approach the system of intermarriage, on which Mr. Walker has so ably written and clearly shewn that as a result we may invariably expect a deterioration of the species. Dr. Darwin has also poetically described what his experience taught him. "So grafted trees with shadowy summits rise, Spread their fair blossoms and perfume the skies, Till canker taints the vegetable blood, Mines round the bark and feeds upon the wood; So years successive from perennial roots, The wire or bulb with lessened vigour shoots, Till curled leaves or barren flowers betray A waning lineage verging to decay; Or till amended by connubial powers, Rise seedling progenies from sexual flowers." The minute nature of the germs of disease preclude all possibility of their being submitted, as far as we know at present, to the inspection of the physiologist, but we may infer many facts from results. In the same way, though with humbler Now concerning the re-production of Cow Pox matter, and assuming it to resemble that of the lower Cryptogamia, we can easily understand how degeneration in a course of years should ensue, for we find that though the Small Pox is a constitutional disease, that produced by vaccine lymph is a local affection, so that it bears the relation that grafting does to vegetation, and it is not improbable that such a modification takes place in the germs by passing through or becoming generated in the blood of the cow, that they entirely lose their original and characteristic form of reproduction: the seeds of the disease were originally capable of vegetating, if I may be allowed to use the term, by diffusion through the atmosphere; they now, however, have lost that property, and require to be grafted to exhibit any manifestation of vitality. How often will the seeds of a cultivated fruit grow? If you bud it upon another plant, you obtain a being exactly like the parent, but this, as we have seen, deteriorates in a course of years, we have also seen that the virus deteriorates; but not to stretch this point to an unseemly length, I cannot avoid expressing my conviction, that these are elements of comparison, possessing an interest and a practical utility of no small value. I have before said, that the reproduction in the Cryptogamia, rather resembles budding than seeding. If we observe the Torula, or take the process of all formation, generally it will be found to accord more exactly with the budding than the seeding process, and this peculiarity is not confined to vegetation, it is also a marked feature in the reproduction of infusoria, sponges, polypes, &c.
The reproduction of plants and animals appears to be of two kinds, solitary and sexual; the former occurs in the formation of the buds of trees, and the bulbs of tulips. The microscopic productions of spontaneous vitality propagate by solitary generation only. We have but reached the threshold of this vast and interesting subject, the experiments which suggest themselves to the mind while reflecting upon it, would alone occupy a whole life of leisure, and I can but feel how forcibly Mr. Sewell's words apply to us: "The grand field of investigation lies immediately before us, we are trampling every hour upon things which to the ignorant seem nothing but dirt, but to the curious are precious as gold." It is difficult, perhaps, to bring many instances, in which the germs of disease have lain dormant for a lengthened period, because many may take exception to them, from the fact, that sporadic cases of The Oidium vitis attacked the vines partially last year, and I believe generally spared other forms of vegetation; but this year in my vicinity, cucumbers, melons, and vegetable marrows, are all suffering more or less under the disease.[37] How shall we say, whether are the seeds of last year the cause of the general diffusion at the present time, or were there a sufficient number of old and dormant seeds, universally diffused, and only waiting opportunities for multiplying themselves? We are here on the horns of a dilemma; and spontaneous generation, from which one naturally shrinks, can alone extricate us, if we do not admit diffusion and dormancy. I think I may, without undue assumption, affirm that a period of latency of indefinite duration, applies as cogently to the germs of disease as to those of plants. There is yet one other point in connection with this subject, and that is the apparent extinction of some diseases, at any rate their non-appearance in certain localities, which had been at one time congenial to them, and in which they flourished. We have seen, in illustrating the dormancy of seeds, that the broom must have been a common plant at Then again, the appearance of Fumaria parviflora in the vicinity of Edinburgh, in several places where the ground is broken, is sufficiently convincing that this plant must once have been a common form of vegetation there; and as it had never before been observed in the neighbourhood, there must have been a combination of peculiar circumstances capable of rendering germination impossible, otherwise a continued multiplication, as in other forms of vegetation, would have followed of necessity. But besides these instances, how many are passing under our own eyes of the disappearance of plants under the influence of cultivation, and the generation of the noxious fumes arising from different and innumerable manufactories. In the vicinity of large cities and manufacturing towns, how rarely do we see healthy vegetation; shrubs and animals drag on a sickly and almost unprolific existence, and their term of natural life is much shortened. And if we compare diseases with this peculiar feature of vegetation, how very close do we find the analogies. The Sweating Sickness which appeared in the latter part of the fifteenth century, and at certain intervals multiplied and extended itself at first only in this country, but ultimately more or less over the continent of Europe, has Since 1665, the Bubo-plague has not found a congenial soil in this country, or if the seeds be here, which is more than probable, the necessary conditions to excite them to activity do not exist. It cannot be imagined that with all the merchandize which comes into this country from the Mediterranean, but that an abundance of the germs of the disease are annually brought into our ports, and disseminated throughout the land. The law by which we have seen that they possess a power of vitality and reproduction, holds now as it did in former times;—the properties of matter never alter, but the conditions under which they exist may be so modified, as to influence their properties, and the usual course of their operations. It is therefore to We have made some few observations and comparisons on the mode of dispersion of plants and diseases,—but there is yet one more point which invites notice. Not only do seasons vary in their effects on vegetation in a remarkable and unexplained manner, but there are many localities to which some special form of vegetation attaches, and which appear to have a power of exclusion of other forms; and as yet I have not been able to trace the connexion, nor can I discover it in the writings of botanists and travellers, who would be most likely to have sought an explanation of so interesting and curious a fact. Dr. Prichard has on this subject some very apposite illustrations. "Still further southward, the austral temperated zone completely I must quote one more passage from Dr. Prichard's excellent work. "We have one instance of an island at no great distance from a continent, having a peculiar vegetation. Mr. R. Brown has remarked, that there is not even a single indigenous species characterising the vegetation of St. Helena, that has been found either on the banks of the Congo, or on any other part of the Western coast of Africa. Does the diversity of marine and atmospheric currents more completely separate this island from the continent, than its situation would imply; or are the nature of soil and other local circumstances, the cause of so marked a diversity? The last supposition seems the most probable; because not only the species of plants, but likewise the genera in St. Helena, are different from those of the African coast." We are not without instances of diseases, observing this peculiarity which attaches to plants; but their specific characters have hardly been sufficiently considered in reference to climate and situation, together with diet and local influences, to afford us accurate data for comparison. It has, however, been remarked, in every country where Epidemics have prevailed, that some districts or tracts of country, though supposed to possess all the qualities favourable to the development of the diseases, have nevertheless been entirely or nearly free from them. The following passage on the course of the Cholera gives an example of this peculiarity. "Whenever the malady deviated, so to speak, from its normal direction, and passed towards the west, it seemed incapable of propagating itself; and died away spontaneously, even in places which appeared to be well fitted for its reception.—The rich fertile and densely peopled countries to the right of the Dneiper, enjoyed an equal freedom from attack, which can only be explained by the fact that they were situated beyond the line of the disease." With this I close the subject of the diffusion of plants and diseases, though it would require a volume of itself, to record all that has been noticed. I have endeavoured to select such instances as shall mark distinctly the features which point to comparison without overloading the enquiry. SECTION IV. THE RELATION BETWEEN EPIDEMIC AND ENDEMIC DISEASES. Epidemic diseases, which multiply their germs in any climate, and under apparently the most varying conditions of temperature and hygrometric and electrical states of atmosphere, offer many points of contrast with Endemic affections, and many of relationship. The latter are traceable to a certain extent, to geological and geographical positions of the localities where they are observed to prevail, in combination with atmospheric vicissitudes and peculiarities, as well as to extent of cultivation of the soil: it has been remarked that the sickly island (as it is called) of St. Lucia has certain salubrious parts, but these are where sulphur abounds; this geological peculiarity has been deemed sufficient to account for the absence of endemic affections in these parts, and with much force of reason; for in the neighbourhoods where sulphur or sulphurous acid, a compound of sulphur, is an element prevalent in the soil or atmosphere, vegetation and the ague disappear together. Now ague, and other endemic fevers, doubtless originate from some allied, if not identical cause; for the localities in which they appear have so many Geographical situation, together with certain vegetation, particularly of grounds which grow rice, is one remarkable for the production of endemic affections. But the soil which generates or gives force to the contaminating matter, is not alone the part where human beings feel its influence most severely. A low marshy ground, prolific of malaria, may be comparatively free; while some neighbouring elevated land, to which prevailing currents of air waft the volatile elements of disease, may be desolated by their virulent and concentrated action. "Malaria may be conveyed a considerable distance from its source, and be condensed in the exhaled vapour, when attracted by hills or acclivities in the vicinity, and when there are no high trees or woods to confine it, or to intercept it in its passage." The inhabitants of the city of Abydos were at one time subject to disease, arising from malaria, generated in some neighbouring marshes; by draining these marshes, which suspended the growth of rank vegetation, the city became healthy. Rome is in like manner even now subject to fevers, having a similar origin. Sir James Clark says, "Among the more prevalent diseases of Rome, malaria fevers are the most remarkable, and claim our first notice." He considers the fevers to be of exactly the same nature as those of Lincolnshire From July to October the inhabitants of Rome are most subject to these affections. Sir James Clark further says: "It may be stated as a general rule, that houses in confined shaded situations, with damp courts or gardens, or standing water close to them, are unhealthy in every climate and season; but especially in a country subject to intermittent fevers, and during summer and autumn. The exemption of the central parts of a large town from these fevers, is explained by the dryness of the atmosphere, and by the comparative equality of temperature which prevails there." In this respect there is a marked difference between an epidemic and an endemic affection; for when an epidemic disease attacks a city or town we do not discover that the central parts are more exempt than others; indeed, it is rather the contrary; for the most crowded parts of towns and cities are those, if not exactly in the centre, which would be comprised in a space nearer to the centre than the circumference; and it has been in those parts generally where the epidemic influences seem to have exercised the most potent sway. One would more naturally suppose, that a city surrounded by Without enumerating all the known endemic diseases, two or three may be alluded to for our present purpose; viz. that of shewing that endemic and epidemic diseases have a similar origin.[39] It is well known that under certain favouring conditions an endemic may become a malignant and pestilential disease; that Yellow Fever, which is always endemic in the west, Cholera in the east, and the Plague in the south of Europe and north of Africa, every few years takes on an epidemic form, and desolates considerable tracts of country.[39] The Pestilence which raged in the summer and autumn of 1804 in Spain, commenced at Malaga, and remained for a considerable time confined to its It appears to be quite clear, that this disease may properly be considered in the first instance of endemic origin; but the tendencies, atmospheric and otherwise, were such as to favour its multiplication in other districts than that in which it first came into active existence. From this we may infer, that the seeds of the disease were dormant, and only became roused into vital activity by fortuitous circumstances. Dr. Rush states, that the endemic disorders of Pennsylvania were converted, by clearing the soil, to bilious and malignant remittents, and to destructive epidemics. Dr. Copland says, it has been observed, especially in warm climates, and in hot seasons in temperate countries, that when the air has been long undisturbed by high winds and thunder-storms, and at the same time hot and moist, endemic diseases have assumed a very severe and even epidemic character. Dr. Robertson also confirms this view. "Endemic diseases, in cases of neglect and preposterous management, are found to become more malignant even in the most temperate climates; and to It will doubtless be generally acknowledged that endemic and epidemic diseases depend upon some unknown agents, having their source in malarious districts, and being capable of assuming either a contagious or non-contagious character, according to circumstances. If, therefore, we find that under any conditions an endemic affection becomes capable of being propagated by contagion, the same law will hold with regard to it as to the Plague; that the power of reproduction in this matter is evidence of life, according to the doctrine laid down in the earlier part of this work. But whether or not infection be admitted, a matter generated in a malarious district, if confined in its effects to that district alone, would not necessarily imply an inorganic nature of the poison; for it is difficult to understand how inorganic poison, prevailing generally over a certain tract of country, could select particular individuals for its victims. If chloroform, chlorine, carbonic acid, sulphuretted hydrogen, or even spores of poisonous fungi, (as The history of the Eclair steamer is particularly interesting, as shewing the extraordinary tenacity with which the germs of disease attach themselves to vessels, which we may call floating houses. The crew of the Eclair contracted Yellow Fever on the coast of Africa, and a number of them died. The remainder, sick and well, landed at Bona Vista, one of the Cape de Verde Islands, and the vessel underwent a process of washing, whitewashing, and fumigating. Nevertheless, on the return of the ship's company, the disease broke out again with equal intensity, and the vessel was ordered home. Sixty-five out of 146 officers and men, who composed the crew, died of the disease before reaching Portsmouth, and twenty-three were sick at the time of arrival. Eight days after the Eclair left Bona Vista, a Portuguese soldier who had mixed with her crew died in the fort which had been occupied by them. Other soldiers then fell sick, and the fort was abandoned. The fever still spread. From the 20th September, when the first soldier This is an abstract of Mr. Rendell's letter to Lord Aberdeen, Mr. Rendell being British Consul at Bona Vista. Now at the time the fever broke out in the island the weather was extraordinarily hot, and much rain had fallen, and the town itself was badly drained and in a filthy state; can it be imagined then that the seeds of a disease liable to assume a pestilential character should lie dormant or be annihilated under circumstances the most favourable for their development, especially when we know that endemic diseases may assume a malignant character? This is just one of many cases which confirm our opinion in this respect, that plants and diseases are not long in making their appearance where the soil and atmosphere are congenial. The tenacity with which the disease attached itself to the Eclair is sufficiently explained in the absence of due ventilation; in fact, that in the first instance there was no ventilation at all in the hold of the ship. This also the more readily affords a clue to the disaster through all its stages, first in the contraction of the disease as an endemical affection in the vessel; secondly, in the multiplication of the The consecutive attacks of the crew of the Eclair shew that here a noxious gas or a vaporized inorganic poison could not have been the cause of the disease, for as I have before said, in this case the attacks should have been simultaneous; we find, on the contrary, that as the depressing effects of the melancholy condition of the crew was almost hourly undermining the health of the stoutest of them they as surely became the victims. The Kroomen, or natives on board the ship had not suffered, shewing that they were inured to the miasm, or were destitute of that condition of blood which would be favourable to a propagation of the materies of the disease. The Eclair we learn had left Bona Vista eight days when the first victim breathed his last; this would give perhaps three or four days for the incubation of the disease in the patient, or supposing he had not contracted the germs of the disease before the crew of the Eclair left the fort, some local favouring conditions were the means of keeping the germs in a fertilizing state, for it is clear from this spot the infection spread as from a centre or focus. To take another instance; intermittent fever or ague, is a disease known among almost all nations of the world, but it usually occurs in the endemic form only. It is universally supposed to depend entirely upon marsh effluvia, and we are accustomed to consider it as attaching only to low lying countries;[40] but this is not always the case, for disease in There are grades and varieties of infectious diseases, from the most inveterate to the most mild and doubtful; but that all, without exception, which can in any way be traced to a specific generating and organic cause, may assume an exalted infectious character, and that the most inveterate, on the contrary, may more resemble the mild and doubtfully infectious forms, is a conviction that must be forced on all who pursue this enquiry with unbiassed interest. CHAPTER III.THE REASONABLENESS OF THE APPLICATION OF THE FACTS TO THE INFERENCE. ———— SECTION I. THE CHEMICAL THEORY OF EPIDEMICS UNTENABLE. It has been inferred that the germs of disease possess the property of vitality, and a number of facts have been adduced to support the proposition that vitality is the indwelling force by which the matter generating epidemic and endemic disease exercises its influence over man and animals. The reasonableness of the application of these facts to the end in view has now to be considered. Chemistry cannot account for epidemics. Our first subject of reflection points to the chemical discoveries of the last few years, and particularly to those of the great German chemist Liebig. We find in the first paragraph of his Organic Chemistry applied to Physiology and Pathology, the following words: "In the animal ovum, as well as in the seed of the plant, we recognize a certain remarkable force, the source of growth or increase in the mass, and of reproduction or of supply of the matter consumed; a force in a state of rest. By the action of external influences, by impregnation, by the presence of air and moisture, the condition The doctrine of Liebig, that the vital force manifests itself in two conditions, or rather, that it is known to be in two different states, that of static equilibrium as in the seed, and in a dynamic state, as in that of growth and reproduction, is perfectly applicable to the germs of disease; the static equilibrium is referrible to the matter of vaccine lymph when dried and preserved for use, and the dynamic forces of the matter are known to be in operation during its reproduction and growth in the system of the vaccinated child. Then as to reproduction of matter by any chemical process, our author can furnish us with no examples, for even in his explanation of the causes of disease he is quite silent on this point, merely acknowledging that diseased products must be either rendered "harmless, destroyed, or expelled from the body." He further says, that "in all diseases where the formation of contagious matter and of exanthemata is accompanied by fever, two diseased conditions simultaneously exist, and two processes are simultaneously completed," and that it is by means of the blood as a carrier of oxygen that neutralization or equilibrium is established. Liebig thus admits that an agent exists in the blood, capable of deteriorating it at the expense of the oxygen, which he maintains is contained in the red globules; he further acknowledges that two processes of diseased If I rightly apprehend his notions, they perfectly harmonize with my ideas, to a certain extent, on the subject. They accord, at any rate, most completely with the theory attempted to be established, and fully confirm the reasonableness of the application of the facts recorded to the inference drawn from other sources. The difference only rests on the question whether vitalized or non-vitalized matter is the fons et origo mali. How is the production of new matter, resembling that originally causing the disease, to be explained by any known hypothesis, except on the assumption of living organized matter? Though Liebig and Mulder both deny the fact, that the Torula cerevisiÆ is the sole agent in the process of fermentation: they both equally fail in shewing upon what it does depend, and their difficulty rests entirely on their incapacity to explain the uniform reproductive properties of the matter engaged in this, as well as in all other allied operations. Liebig's statement This state of decomposition, however, involves a much more complex proceeding, than simply a reduction of matter into its elementary forms of gases, earths, and minerals; for we nowhere find decomposition of this kind going on without the development of some organized bodies, either animal or vegetable: and since we have seen that the spores of the cryptogami are always in existence in the atmosphere, and making their appearance under favouring conditions, and especially when we find that fermentation is invariably accompanied, and I may safely say, preceded by the deposition in the fluid of the sporules of the Torula, we can hardly believe that they are any other than the sole agents of the process. I have now a considerable quantity of the Torula obtained from the urine of a diabetic patient, in which they appeared, as it were, spontaneously. After the urine had been allowed access to the air for a certain time, and the whole of the saccharine matter was converted into new compounds, reproduction of the Torula ceased;—and those which remained when the process was completed, still continue as organic cells, deposited Mulder, however, does allow some properties to the yeast vesicle; he says, "a variety of strange ideas have been entertained respecting the nature of yeast; recent experiments have convinced me that it undoubtedly is a cellular plant consisting of isolated cells. They resemble the composition of cellulose in some respects, but differ from it in many." "These vesicles, consisting of a substance resembling that of cells, do not contribute in the least to the fermentation, but are exosmotically penetrated during fermentation by the protein compound." These chemists seem to have an instinctive horror of allowing any active properties to the yeast vesicle, that is as far as the conversion of sugar into carbonic acid and alcohol is concerned in the act of fermentation. Dr. Carpenter, as if desiring to conciliate the chemical and physiological disputants, considers that the truth is to be found in the mean of the two extremes,—that is, that the process of fermentation is neither entirely dependent on chemical laws, nor on those laws which preside But to revert to Mulder, he speaks of the Torula cells being "exosmotically penetrated during the process of fermentation by the protein compound." Now the Torula is acknowledged to be one of the Fungals, and the chemical constituents of the Fungi approach very nearly that of animal tissues. They contain a peculiar principle, residing in and obtainable from them, termed Fungin, which is as highly azotised as animal fibre. The protein compound alluded to, Mulder says, is not gluten, because insoluble in boiling alcohol, and not albumen, because it is very readily dissolved in acetic acid, and he regards it as a superoxide of protein. This superoxide of protein can only have been produced by a vital action in the cells of the Torula, and as the fungi consume oxygen, and give out carbonic acid, we clearly have all the elementary conditions for their growth in almost all decomposing animal and vegetable matters. It is the nature of the fungi to live on organized matter, but always when it has a tendency to decay; it is for this reason they have been called "Scavengers." Again, we can understand why some animalized or nitrogenous matter should be necessary for fermentation, otherwise fungi could not grow, nitrogen being an essential constituent of
If therefore the process were merely of a chemical nature, where is the necessity for atmospheric oxygen to accomplish the end? it is quite certain that fermentation cannot go on without its presence. Let us compare the action of ferment or yeast in a dried state to the action of albumen, which Liebig says is sufficient when decomposing to set up fermentation. "The white of eggs when added to saccharine liquors requires a period of three weeks, with a temperature of 96° F. before it will excite fermentation."[42] But any saccharine liquor on exposure to the air, though entirely destitute of albumen or gluten, will ferment, and the Torula may be found in it. I have found the Torula in a great variety of syrups which have spontaneously undergone fermentation. I have also discovered that the development of the cells is delayed or accelerated by the nature of the ingredient used in flavouring But the conversion of starch into sugar by means of gluten requires some notice, as by some persons it is associated in their minds with the organic process of fermentation.[43] Mulder ascribes the latter in the first instance to the action of heat, evidently believing that the pseudo-catalytic operation of gluten upon starch is the type of all such actions, and regarding them all as simply chemical, but we here distinguish a wide difference; in the latter instance the gluten is decomposed, and rendered unfit for a repetition of the chemical phenomenon, and if it is desired to renew the action fresh gluten must be obtained, and a certain temperature kept up, otherwise the experiment fails. How different is fermentation: in the ordinary temperature of the atmosphere the yeast vesicle will multiply, no incremental or unnatural addition of heat is requisite, and it is one of the commonest and most natural instances of vegeto-chemistry: the grape cannot shed its juice, nor the sugar cane its sap without admitting these germs, which, under certain Four points of contrast present themselves for notice as elements of comparison with true fermentation. 1st. The starch solution has to be boiled, so that heat, by which it is to be supposed that the starch globule is ruptured, seems to be an essential portion of the chemical change, and even this may in fact alone be sufficient in such a case to produce some elementary change in the starch, and may prepare it for the subsequent catalytic action of some related organic, though not vital material.[44] I have been thus particular in commenting on this subject, as it bears, in an especial manner, on the question under consideration. The physiologist cannot afford to lose this process from the category of chemico-vital, or biochemical manifestations.[45] The philosophy of the age has a tendency to make every thing chemical; it is true that the Divinity is as much seen in the laws which govern the elementary particles of matter, as in those laws which preside over the transmutation and sustentation of those elementary and inorganic particles, when compounded in the tissues which are engaged in the formation of living beings. The laws by which acids and alkalies neutralize each other, and the affinities single, double and elective, which the particles of matter exhibit, together with the influences of light, heat, and electricity upon almost every condition of matter, are as truly wonderful as the creative power. Man may, in many instances, imitate the processes of nature, he can render iron magnetic, and form alkaloids, but the To return, as we every where in nature find a gradual transition in the forms, arrangements and properties of matter, so we may expect to find a link between the inorganic and vital chemistry of nature. The fungi, by which we contend this transition appears to be accomplished, are also a link in chemical composition, between the animal and vegetable kingdom, and not only in that, but in their subsisting upon matter which has been organized, they are deoxidizers and reducers, as the vegetable kingdom in its highest function is a compounder. To their functions and offices in the great scheme of creation, we may fairly apply ourselves with a sure and certain result of the most interesting discovery. Is it no hint that wherever decaying organic matter is found, there do we find fungi? is it no hint that they are found in all parts of the world? that even in snow the germs of fungi will grow and multiply to such an extent, according to Capt. Ross, that the protococcus was seen Even stones contain in their interior, or interspaces of their structure, the germs of fungi. A species of Tufa is found in the vicinity of Naples of a porous texture, which, when moistened and shaded, produces vast mushrooms, four or five inches high, and eight or ten inches broad.[47] This author further says: "In the Maremma, where the volcanic tufa is the basis of the soil the surface is intermixed with the animal remains of departed empires, and the ordure of cattle, is covered with grasses of old pasturages, and is wet with heavy dews. Everything, therefore, conspires there to a fungiferous end." They are found growing in and upon both vegetables and animals. Nees von Esenbeck imagined, that minute forms multiplied themselves in the atmosphere; and really, when we consider the amount of effluvia composed of the atoms cast off from the bodies of living or decaying organic matters, which are incessantly passing into the atmosphere, the conjecture is not an unreasonable one. The minuteness of those, which we know are always found growing on decomposing bodies, does not preclude the possibility, nay, further favours We can, therefore, I think, conclude, that the lower tribes of vegetation, may consistently be regarded as capable of existing in almost any condition, and almost under any circumstances, they may be made to grow in plants by inoculation, as shewn by De Candolle, and Dr. Hassall. If the stem of wheat also is inoculated with vibriones, they will make their appearance in the grain.[49] If the seed contain them and have not lost its germinating properties, these worms will be found again in the grain. If the grain containing them be dried for years, and moistened again with water, these animalcules, according to Bauer and Steinbach, will present all the phenomena of life. This experiment I have witnessed, and can confirm the statement. These animalcules in the diseased grain, have under the microscope the appearance of an immense The chemical theory of disease would be better sustained by a comparison of "the artificial formation of alkaloids," and the phenomena of transformation of blood into the tissues of animals, and their degeneration into effete matters, and of sap into the tissues of plants and their degenerations. Professor Kopp of Strasburg, says, "In a chemical point of view, the alkaloids are remarkable for their composition, for their special properties, both physical and chemical, and for the interesting reactions to which many of them give rise, when exposed to the influence of different reagents. Considered medically, the organic bases are distinguished by their energetic properties. They Upon this very intricate and interesting part of chemical philosophy, it is rather dangerous to enter without a thorough and practical knowledge of the subject. This, however, falls to the lot of few men. We, who are engaged in the study of disease, and of the best methods of cure, are obliged to take the investigations of the analytical chemist, and examine them for ourselves in the intervals of leisure allowed us during the active exercise of our calling. Though with less advantages for the study of these transcendental relations of organic and inorganic matter, we are not, nevertheless, precluded from forming our opinions on their practical bearings to the phenomena and treatment of disease. That there is a matter of a poisonous nature concerned in the production of endemic and epidemic affections, cannot be doubted by any one; I believe indeed, that the chemical theorists admit this, at all events Liebig does, for he says, "The morbid poison changes in the blood are fermentative, just such as occur in beer making." If we start, then, with the consideration that poisons, in a chemical point of view, are the objects of our research; the obvious course to take is to enquire what is the source of poisons generally, and what their effects on the animal economy? The mineral poisons are entirely excluded from the enquiry by their But supposing that the generation of alkaloids could take place in the body, or some analogous poisonous matter, we have yet to imagine a whole host of peculiar and essential conditions to effect this change, besides an atmospheric agent or agents to set in motion those compositions and decompositions, capable of bringing out these new products from the elements of blood. We are aware that in the blood, carbon and nitrogen are sufficiently abundant as well as saline compounds, to generate cyanides, and, with hydrogen also there in plenty, hydrocyanates, and thus from them many other poisonous products, but how is all this to be effected? And even if effected, it is yet a question if such compounds can in any way simulate the attacks of epidemic disease. We have The catalytic process, by which decompositions are said to be effected, and in which Liebig includes the various fermentations, is one of those chemical relations of matter to matter, considered by some as the probable cause of infection. Mr. Simon, in a late lecture, has said, "I consider the phenomena of infective diseases, to be essentially chemical, and I look to chemistry to enlighten the darkness of their pathology. Qualitative modifications, affecting the molecules of matter as to their modes of action and reaction, are such as form the subject of chemical science; and those humoral changes which arise as the result of infection clearly fall within the terms of its definitions." Further on he adds: "The phenomena of infected diseases appears then, in many respects, to be sui generis. Certainly they are chemical. Probably they belong to that class of chemical actions called catalytic."[52] It is not improbable that something resembling a catalytic action may take place in the blood in those diseases of endemic and epidemic origin, but that it can be by a chemical process alone is contrary to all experience of catalytic operations, for except in the instance of fermentation proper, there is no multiplication of the fermentative matter. The action of the matter of contagion seems to stand on the confines between electro-chemical and bio-chemical manifestations, and so long as no chemical explanation can be given for the multiplication of the matter of infection, the most rational course to adopt is to assume that life under some unknown form is, as we every where find it, the sole reproductive agent. SECTION II. THE ANIMALCULAR THEORY OF EPIDEMICS UNTENABLE. The animalcular theory of disease, after remaining almost unnoticed for nearly two centuries, has been again revived under the auspices of Dr. Holland in this country, and Henle of Berlin. And though not entirely buried in obscurity, this theory had completely failed to modify the practice of physicians in the treatment of those diseases which were supposed to owe their existence to these invisible atoms of created being. The resuscitated notions and all their amplifications, to which the advance of science has contributed so much, are threatened with a like fate, an absence of all practical results. Though I would not attempt to deny the possibility, nay, even the probability, that insect life may yet be discovered as the cause of some diseases,[53] still Disease, in its most enlarged sense, is a conversion of one form of matter into another; it is a transformation of healthy blood and tissue into new and abnormal products. Where insects in all their variety of forms are discovered, their voracious propensities are their chief characteristics, they are the consumers of matter after its partial disintegration, if animal matter be their food, unless they be carnivorous and predacious, or if herbivorous they usually feed upon the tender shoots of plants. Thus far we are certain of the manner in which insects destroy living matter; it is a process the unassisted eye may every where witness, and which experience has amply attested. To take, however, the animalcular world as it presents itself to us under the microscope, and as the intermediate step between the manifest and the hidden for a fairer and more direct method of reaching the truth, what do we observe to be the ruling law of infusory instinct? They live to feed; the term polygastrica sufficiently implies their natural tendency to consume. The simplest form of animalcular life, seen in the genera of monads, still preserves the animal character by possessing a stomach or stomachs in which the food is received, to be digested for the nourishment of the But Ehrenberg's scrutiny corrected the error of De Blanville, and shewed, that they were far from being agastria, or stomachless animals. The Rev. William Kirby says, "Ehrenberg has studied the vibriones in almost every climate, and has discovered, by keeping them in coloured waters, that they are not the simple animals that Lamarck and others supposed, and that almost all have a mouth and digestive organs, and that numbers of them have many stomachs." All the discoveries indeed which have been made on the minuter forms of animal life, have tended to confirm the doctrine that the stomach is the exponent organ of an animal; that is, in all animals there exists, in a variety of modified conditions, a receptacle for food. Some of the So far then for the consideration of animalcular structure: let us now more particularly enquire into their destructive habits, and their functions, inasmuch How do these animals obtain their sustenance, and what changes can they produce upon the vital fluid of the body? Analogy is here our only guide. If the trichina spiralis is examined, it is found to be enclosed in a cyst containing fluid; and this is, We have alluded to the vibriones which are found in the fluids of living bodies, and the trichina which is found in the solid muscle; we have now to refer to those which infest the cavities. It was, I believe, Ehrenberg, who shewed that the tartar which accumulates on the teeth is composed of the debris of minute animalcules; in fact, that it consists of calcareous matter, having once formed a portion of the structure of their bodies, the ubiquity of these creatures is therefore as much and clearly established as the lower forms of vegetation. The intestinal worms, of which perhaps the TÆnia is the most curious and important to be noticed, are from the locality in which they are found, chiefly injurious by the irritation they set up, and by appropriating We thus arrive at the simple cell, and the multiplication of living beings by cell buds; it is the point at which the confines of the animal kingdom are reached, and at which we are driven to speculation. The hydatid lives like a plant, by imbibition; and procreates, like a plant, by budding, either endogenously or exogenously, as regards the original or parent cell.[57] This condition of being, suggested the notion of Protozoa, or first animals, in the same way that the purely cellular plants, that is, each individual, consisting of a single cell, gave the idea of Protophyta, or first plants. Mr. Kirby thus expresses himself on this subject: "The first plants, and the first animals, are scarcely more than animated molecules, and appear analogues of each other; and those above them in each kingdom represent jointed fibrils." Admitting, then, that animals as well as plants exist in the form of simple cells, and that their multiplication proceeds apparently upon the same principle in each, it is nevertheless abundantly manifest, that the cellular form of perfect individuals is infinitely more numerous in the vegetable than in the animal kingdom. From the mosses downwards to the fungi, the whole structure of the plants consists of an aggregation of cells, more or less in number and complicate arrangement, until, through a variety of gradations, we reach the single cell as a perfect individual. It is rather remarkable, that the lower forms of vegetables and animals seem to derive their nutriment from matter of a similar kind; and though the office of plants is as a rule, to convert inorganic into organized matter, it appears that some of the fungi may live as animals do on organic matter when in a state of solution. This, however, is uncertain; for we do not know what are the first signs of decomposition in organized bodies, and for aught we can tell, it may be perpetually going on; so far as the disengagement of carbon from the system is concerned, this is certain; but whether the nitrogenous compounds also are subject to a resolution into their elements in the living body, is another question, and not so easy of solution. The partially decomposed elements of animal structures are, however, particularly adapted for the nutrition of the lower forms of vegetation; it is, indeed, from the decaying organic matters that the fungi derive, it may be said, their entire food. SECTION III. SKETCH OF THE PHYSIOLOGY AND PATHOLOGY OF PLANTS AND ANIMALS. Animals and plants depend for their existence upon a nutritive fluid, which permeates their structure; it is the element from which all their secretions are formed, and their organs are nourished. The food of animals is composed of previously organized matters, and is conveyed into a reservoir called a stomach, where it undergoes a process of solution, previously to entering the circulation. At this period, the animal and the plant again present points of resemblance, the lymphatics or absorbent vessels take up the products of digestion, and convey them to the blood-vessels, where mingling with the current of the blood, they are conveyed to the lungs, there to undergo a process of oxygenation before they become fitted for the renovation of the tissues of the body. Such is the nature of the food of man, that it contains all the elements necessary and adapted for transformation into bone, muscle, brain, and parenchyma, as well as the other tissues of the body; besides other elementary matters, which, though they form a very insignificant portion of Plants do not require a stomach,—the humus or soil to which they are fixed is the laboratory, where the nutritive matter is prepared in a state fit for absorption by the spongioles of their roots, and these correspond to the lymphatics of animals; after being taken up by the spongioles, this new fluid mingles with the sap, and passes to the leaves or breathing apparatus of plants, where carbonic acid gas combines with the crude vital liquid, and converts it into a condition fit for all the offices to be performed by the plant: viz. the growth of tissues, and the elaboration of secretions. The tissues, however, of plants, though more simple in their nature, present a much more varied character than those of animals, when the different species are compared. The bones of animals which give them their form, are invariably constituted of phosphate and carbonate of lime, deposited in a matrix of gluten; muscle, nerve, brain, tendons, and ligaments, have nearly, if not completely, an identical composition throughout the whole range of the animal kingdom: their secretions, however, vary much more considerably, as also do the secretions of vegetables. But vegetable tissue may contain, as in the stems of Thus, whether we regard the health of animals, or vegetables, we discover, that besides the matters which are absolutely indispensable for the nutriment of the tissues which undergo rapid transformation, those of a more permanent and durable nature require in an almost insensible degree, a restitution of elements; and though not apparently absolutely necessary to preserve vitality in the being, yet have so marked an influence over it, as to indicate an extensive bearing of each individual part, on the whole associated entity. The elementary tissues of both kingdoms have been traced, in whatever form they may be found, to a cellular origin. The minutest vegetable germ, is a cell containing a granular matter within it, and even man himself, in his embryonic state, may be represented as an insignificant point in the realms of space; and might be placed side by side with the smallest particle of living matter, without suffering by the comparison. The laws by which the development of these elementary cells is regulated, so that each advances The organization of the two animated kingdoms, is then regulated by definite laws, and all matter, whether acting upon them as agents of nutrition or destruction, are equally under their dominion; to investigate and to endeavour to fathom some of these laws, is the aim I have in view. The sap is to the plant, what the blood is to the animal,—the elements of nutrition and secretion are contained in it, and whatever interferes with its normal constitution by subtracting from, or adding to it, deteriorates its qualities, and retards or accelerates the functions of the individual. Excess or deficiency of the natural elements may also be a source of disturbance; if carbonic acid be too abundantly liberated in the soil, as Dr. Lindley expresses it, "plants become gorged;" and if, on the other hand, the elimination be too slow, they become starved. It has been also shewn, that plants though they give out oxygen from their leaves, do not throw it off as animals do carbonic acid from their lungs; but that this arises as a result of digestion, and the fixation of carbon in the system, and that they really respire oxygen as That light is the stimulant of the digestive functions, and that, therefore, during the day, the amount of oxygen thrown off, far exceeds the amount of carbonic acid liberated during the same period. The great and important distinction between animals and plants is, that the former possess a nervous system, by which they are subject to a very extended series of psychological relations; it is in these chiefly, if not entirely, that we are to look for the distinctive and well-marked differences of diseased action. In animals there are special media of communication between the sources of dynamic power, and the parts upon which the force is exercised: and again, a return communication exists, which conveys impressions to the source of power, and to use a simple comparison, a system of telegraphing is in incessant and watchful operation. This force is influenced and modified in its action, when exercised in the regulation of nutrition, growth, and reproduction of tissues, by the passions and emotions of the mind. All the secretions and functions of the body are more or less susceptible of being accelerated, retarded or modified by the psychical relations of mind and matter. Though we are apt to imagine that in man alone, these phenomena obtain much importance—there can be but little doubt, that wherever a The diseases of plants and animals deserve a more careful comparison than, I think, has hitherto been bestowed upon them.[58] If the study of physiology, or an enquiry into the laws which regulate the functions of living beings in a state of health, has been materially aided by the intimate knowledge of vegetable physiology, which, from the simple structure of plants, so favours the experiments of the student, there is every reason to suppose that vegetable pathology may also lead us to an equally important and useful result. It is quite certain, that if a healthy seed, or leaf-bud, be placed in such a situation, that, according to the laws known, it will in all likelihood germinate, if all the elements for its sustenance exist in the soil, and the temperature and hygrometric Yet how many points of resemblance are there between the vegetable cell and the fully developed human being, in a physiological and pathological point of view. There must be nourishment to sustain both; both require a certain amount of light But during the existence of plants and animals, we discover other features of comparison; plants, as well as animals, are liable to disease; they are subject to functional and organic affections. The former, among plants, are usually traceable to atmospheric vicissitudes or irregularities, changes of situation, &c.; and in man to irregularities of diet, and mental and bodily excesses, as well as to atmospheric vicissitudes.[59] The organic diseases of plants and animals depend upon a repetition, or continuance, of functional derangement. As a consequence of this, the nutrition and reproduction of tissues lose their normal and definite character, wherefrom an indefinite and abnormal result is obtained. There is a limit to abnormal productions, and they are apparently In plants, from their greater simplicity of structure, organic affections are perhaps entirely limited to the two first forms of animal organic disease; viz. to undue development of tissue in natural situations, and to the formation of natural tissue in parts of a plant where they are not usually found in a state of nature. The variety of excrescences seen on the stems, branches, and twigs of plants, may be given as instances of the former; and the conversion of stamina into petals, as in double flowers, as an instance of the latter. We derive our sustenance from vegetables, and they from us; they produce for us the soothing opiate and the deadly strychnia; we for them the animating ammonia, and the distortions and sterility of excessive culture; we engender in them, by the latter, debility, disease, and death; and in our turn we become their prey. All this indeed is but a cycle of events, that requires no learned mind to fathom, and to comprehend; it is a matter of every day occurrence, and, though perhaps not entirely unheeded, is not dwelt upon in the fulness of its bearings and importance. Let us now consider the diseases of plants, as a study progressive to those of man; and as their physiology has so extensively served us, we may possibly also find in their pathology much material for instruction; not that it will be attempted to shew that the same diseases affect both kingdoms, but that diseases, though dissimilar in effects, may have similar sources. Unfortunately, there are not many men in this country, who need go further than their own gardens to find abundance of disease among their fruit trees and vegetables. The vine, the apple and the potato, common to most gardens, will furnish specimens. It is an error of a serious kind to suppose, that the parasites which infest plants are not essentially the cause, or, perhaps, more properly speaking, the elements of disease. I confine myself here to disease of parasitic origin, as that is the subject of which I am chiefly treating. That parasitic growths are the elements of disease in some instances, is now beyond dispute. The experiments of Mr. Hassall, detailed in Part II. of the Transactions of the Microscopical Society of London, are most conclusive; and they are of that simple nature, that any one may convince himself of their accuracy, by a repetition of them from the directions there laid down. He says, the decay is communicable at will "to any fruits of the apple and peach kind, no matter Mr. Hassan, however, seems to speak doubtfully as to the mode in which the disease becomes naturally introduced;[60] how the spores enter the fruit, "is not very clear—though probably, it is by insinuating themselves between the cells of which the cuticle is composed, or perhaps by means of the stomata, where they are present. I may here state that the experiments were made on fruit, while living, and attached to the tree." But why should there be a doubt as to the parts by which the sporules of minute fungi enter the plant, when it is clear, that not only can they enter On referring to Dr. Lindley's Medical and Economic Botany, I find that many fungi are the active elements of disease, and in a manner which renders it highly improbable that they are so in any other way, than by obtaining an entrance to the sap of the plants. Of the microscopic fungus which destroys wheat, the Uredo caries of De Candolle, we find the habitat to be within the ovary of the corn, and that 4,000,000 may be contained in a grain of wheat,—now this and another fungus, the Lanosa nivalis, are said to destroy whole crops of corn: we cannot imagine that such an extensive affection, can have any other source than by means of the spores through the sap, seeing that bruising of the surface, or rupture of the cuticle of the apple, a comparatively soft fruit is necessary to produce the disease artificially in them; besides, a grain of corn containing vibriones, when grown and having fruited, the new fruit also contains them—now here, as this is I believe almost invariably the It is rather a remarkable fact, that these entophytes appropriate the nutriment destined for the plant in which they grow, they are consequently the means in many instances of its entire destruction, though only partially so in others. There are many Fungi which have this tendency. The Puccinia gramienis, "preys upon the juices of plants, and prevents the grain from swelling." The Æcidium urticÆ, common on nettles, deprives the plant on which it grows, of the organizable matter, intended for its own nutrition. The Erysiphe communis, overruns and destroys peas. The Botrytis infestans, "attacks the leaves and stems of potatoes." The Oidium abortifaciens, attacks the ovaries of grasses—and the Oidium Tuckeri, "a formidable parasite, destroys the functions of the skin, of the parts it attacks." The latter has been most injurious to the vines, during the last two years. I have known instances in which the vines have been cut down, and every means taken to rid the houses of the disease; but this year, it has made its appearance, with all its former virulence, in the new shoots. This, however, is sufficient to shew that plants are liable to disease, depending upon parasitic growths, which affect their vital powers, and deprive them of their natural nutritive fluids. But somewhat similar diseases belong also to The West India sugar-canes are also liable to a disease, which the Rev. Mr. Griffiths, in his Natural History of the Island of Barbadoes, speaks of, in the following manner: "This, among diseases peculiar to canes, as among those which happen to men, too justly claims the horrible precedence." This disease is called the Yellow Blast. It is difficult to distinguish the Blast in its infancy, from the effect of dry weather. There are often seen on such sickly canes, many small protuberant knobs, of a soft downy substance. It is likewise observable, that such blades will be full of brownish decaying spots. The disease is very destructive to the canes. It is observed, that the Blast usually appears successively in the same fields, and often in the very same spot of land. This Blast is often found far from "infected places," and the infection always spreads faster to the leeward, or with the wind. "It is remarkable if canes have been once infected with the Blast, although they afterwards to all appearance, seem to recover; yet the juice of such canes will neither afford so much sugar, nor so good of its kind, as if obtained from canes which were never infected." I may here allude to the circumstance, that in the island of Cuba, the destructive mildew is commonly called, la pesta. It were needless to multiply instances of other endemic and epidemic diseases of vegetables; they are well known by practical observers to be very numerous, and I believe, in most instances, depending upon fungoid growths. The destruction of vegetables by insects, is of a very different nature to that produced by the fungi; it would be as unreasonable to consider the consumption of corn and herbage by locusts, as a disease of vegetation, as the massacre and devouring of human beings by cannibals, a disease of the human body. It is true that insects are exceedingly destructive to plants, but as far as I am able to obtain information, they appear to be so chiefly by their voracious propensities; they consume the structure of the plant in its entity, and do not primarily interfere with its vitality. The instance of the vibriones, before-mentioned, seems at first to be an exception Having now considered the question as to the infeasibility of supposing that chemical fermentation is the basis upon which a theory of diseases can be sustained, and having shewn that life is inseparable from infection, and miasmatic generation;—having explained the phenomena of the dispersion of diseases by comparison with the dispersion of plants, and finally, having demonstrated that the physiology and pathology of plants bear so close a relation to each other, and that their epidemic affections depend upon minute organic germs, I submit to the judgment of my readers, whether there is not much reasonableness in the application of the facts to the inference—that living germs are the cause of epidemic disease in man and animals. CHAPTER IV.RESULTS IN PROOF OF THE TENABLENESS OF THE PROPOSITION. ———— SECTION I. OBSERVATIONS ON SOME OF THE LAWS OF EPIDEMIC DISEASES. The results obtained by comparing certain facts connected with Epidemic Affections of animals, with analogous affections in plants, afford, from the few instances I shall here notice, a very strong presumption, that analogous causes operate in the production of these affections. I have already quoted from Hecker, to shew that previously to, and during the Epidemics of the Middle Ages, the minuter forms of animal and vegetable life appeared to be called into existence, much more abundantly than usual; that famines prevailed in consequence of failure of cereal crops, no doubt depending then, as now, upon the various forms of fungiferous growth. I cannot refrain quoting here, a passage or two from our old friend Virgil; for he confirms not only the fact of peculiar showers in 150. "Mox et frumentis labor additus; ut mala culmos Esset rubigo ... ... Intereunt segetes." Georg. 1. Then: 311. "Quid tempestates autumni et sidera dicam? . . . . . . 322. "SÆpe etiam[61] immensum coelo venit agmen aquarum Et foedam glomerant tempestatem imbribus atris CollectÆ ex alto nubes." Georg. 1. The occurrence of black showers in this country has been observed during the present year, and I understand that in the fenny countries of the East, the corn has suffered much from the Uredo. I am not mentioning the circumstances as cause and effect, but merely to call attention to the fact, that unusual phenomena of this kind have been generally associated with disease of the animal and vegetable tribes. The same causes also predispose plants as well as animals, to epidemic attacks of disease. The repeated observations in the public journals on the subject of ventilation, drainage, and over-crowding, render all notice from me needless, to shew that these, though they do not produce the diseases Lastly, says the Count Philippo RÉ, "I would remark that if bad cultivation, and especially bad drainage, does not produce bunt or smut, it is certain that those fields, the worst treated in these respects, suffer the most from these diseases." It has been remarked by many observers, that a greater fecundity has attended upon Pestilences, and this has been proved by comparison, that the births in proportion have far exceeded the ordinary limit.[62] In juxtaposition with this observation, I will place the following, not as a proof, but as a remark made quite independently of the subject of which I am treating. "From the first the diseased ears are larger than the healthy ones, and are sooner matured. What appears singular, but which I have not, perhaps, sufficiently verified, is that the seeds are more abundant than in a sound ear." Now these are facts which require amplification, and if these two alone should be shewn upon an extensive field of observation, to apply not only to corn, but to other members of the vegetable kingdom, as I doubt not will be the case, though I am not fully prepared to prove it, it would be difficult to dissociate the fertility of the two living kingdoms from the operations of one and the same, or an analogous law. The epidemic diseases of plants are both infectious and contagious, at times they are observed to be endemic only, and then depending particularly upon some local causes. This is a law of diseases which applies equally to those of men and animals. In connexion with this law is another, which, as far as I am aware, has not hitherto been noticed in connexion with plants. The potato disease, which excited so much interest and created so much anxiety for the poorer classes of society, led the Government of this country to employ the most learned men to investigate the subject, in the hope of propounding some reasons which should explain the cause of the calamity, and thereby deduce a method of eradicating the evil, or, in other words, discover a cure for the disease. Many were the opinions as to the cause of the distemper, which it were useless here to recount, but a method was suggested, to which most people, I believe, looked forward with great anticipations, and this was to obtain native seed, and to sow it on virgin soil. Was the end accomplished? No. As a parallel to this, it may be stated, that, as regards either endemic or epidemic disease, those persons newly arrived, either in a district or country where these prevail, are even more liable to them than the residents.[63] Again, I have learned, that where the potato disease has been so bad as to render the crop almost valueless, the best plan to be adopted is, to allow the plants to remain in the earth, and thus leave such as retain their germinating powers to come up spontaneously the following year. I certainly saw one large field treated in this way, yield a crop almost without disease. The seasoning, in this instance, seems to bear a comparison with the seasoning of animals and man, under a variety of diseases, which for a time renders them insusceptible of another attack. It therefore does not appear so improbable, that these affections may be regarded, as Unger, the German botanist supposed, the Exanthemata, or Eruptive Fevers of vegetables. Another feature seems to associate the Epidemics of plants and animals, in a manner suggestive of analogous causes operating in both instances. The lungs of animals and the leaves of vegetables, are their respiratory organs, by means of which, the blood in the one case and the sap in the other, derive gas from the air, and impart gas to it, each taking what is thrown off by the other. Now the epidemics among vegetables, have a remarkable tendency to exhibit their effects primarily on the leaves, and particularly on those parts which are appropriated to the function of respiration. It is from the stomates that many of the fungi commence to germinate, and their fructification may be seen sprouting from the opening composed of a chink, surrounded by a peculiar arrangement of cells, which constitute the breathing apparatus of their victim. In the earlier epidemics, of which we read, one of the most remarkable circumstances, was the extraordinary influence the poisonous matter appeared to It is more than probable that all infectious matter obtains an entrance to the system through the lungs. Inspiring the air containing the pestilential semina is, indeed, the only plausible explanation of infection; for though the skin is indubitably an absorbing Many facts are on record which prove the powerful effect of diseased grain when made into bread, and taken for any length time as a principal article of food. The history of Ergot of Rye is too fresh in the memory of most people to require more than an allusion here. The stomach had no power over the secale, its poisonous properties were retained, after having been submitted to the digestive process, as was evidenced by the abortions and gangrenes it occasioned. But diseased wheat is also capable of inducing What other afflictions may be due to diseased vegetation and adulterated articles of food, and what loss of life may accrue from cheap and adulterated To return,—associated with these observations are other facts of considerable weight. Before and during pestilences, abortions are more frequent than in ordinary times; infectious and contagious diseases induce abortion; besides this, and independently of disease, conditions of the atmosphere have been known to exist when abortion has been an epidemic affection; of this Dr. Copland says, "to certain states of the atmosphere only can be attributed those frequent abortions sometimes observed which have even assumed an epidemic form, and of which Hippocrates, Fischer, Tessier, Desormeaux, and others have made mention." With this reference I will close the subject of comparison between the affections of the breathing apparatus in animals and plants, merely alluding to the probability that under some conditions of atmosphere, independently of heat, &c. vegetables without any other assignable cause will become abortive. SECTION II. WHAT IS THE NATURE OF THOSE POISONS WHICH MOST RESEMBLE THE MORBID POISONS IN THEIR EFFECTS ON THE BODY? In the early part of this book, I considered the nature of poisons generally, and had occasion to remark upon the characters which separated poisons into two distinct classes. 1st, Those which have the power of self multiplication; and 2nd, Those destitute of this property. Of the first we have seen that the poisons of epidemic diseases multiply both in and out of the body. The poisons of infectious diseases, not usually epidemic, do the same. Those of endemic affections, such as ague and some fevers, usually become multiplied out of the body only, but under some circumstances, and peculiar atmospheric conditions, they may be also multiplied within the body. The amount of these poisons necessary to produce their specific effects, may be inappreciable. Of the second class, there are two kinds, those derived from the organic kingdom and those derived from the inorganic kingdom. Of these, the amount necessary to produce their specific effects is appreciable and pretty well known. But among those poisons, consisting of organic This property of the amanita, at once places it in a separate category from all other organic poisons, it has yet to be shewn upon what this intoxicating fungus depends for its activity. Whether some secretion is formed in the tissue of the plant, or whether some new arrangement of the particles of matter or modification of the sporules, is brought about by entering the system, it is impossible to say. Langsdorf states that the small deep-coloured specimens of amanita, and thickly covered with warts, are said to be more powerful than those of a larger size and paler colour. As the effect is not produced until from one to two hours after swallowing the bolus, and as a pleasant intoxication may be obtained by this agent for a whole day, and from one dose only, there is a defined line between this and the ordinary narcotics and stimulants in common use. That the digestive powers of the stomach have no influence over the intoxicating properties of the plant, is manifested in the fact, that the active principle passes into the urine, not only not deteriorated but apparently increased, for, as we have seen, a teacup of the urine from a man, intoxicated by taking the amanita into his stomach, will cause him to be more powerfully intoxicated than by the As to the first class, or truly reproductive and Now, the morbid poisons, if studied only in their results, shew that there is a combination of these two actions. There is usually, in the first place, a toxic or poisonous action, and secondly, a deteriorating or decomposing action on the blood, by which there is a tendency to low or asthenic inflammation and gangrene. It matters not what form of fever we take as an illustration, whether intermittent, pestilential, or exanthematous, either will serve the purpose of shewing how completely the effects of vegetable organic poisons resemble those which for the sake of distinction (I suppose) have been denominated Morbid Poisons. Take an attack from the paludal poison. It is If we take the effects of poison of Erysipelas, of Scarlet Fever, or Plague, in each we find at the onset more or less general derangement of the system, usually with cerebral disturbance and disordered action of all the dynamic forces of the body, which clearly indicate the action of a poison; then, unless some favourable symptoms arise, the blood exhibits a steady advance towards disorganization, and sphacelation of one or more tissues or parts of the body ensues. In Erysipelas the force of the diseased action is expended on the skin, and subcutaneous cellular tissue; in Scarlet Fever the fauces ulcerate, and slough and the parotids suppurate; in the Plague there is a general tendency to putrefaction, and the formation of glandular abscesses with sphacelas. Without going any further into this matter, for my present intention is merely to draw We know that the fungi are poisonous, that at times and seasons, and under variations of climate, they vary in their effects, and perhaps lose altogether these properties. We know that the fungi produce gangrene of the tissues, and disorganization of the blood; we know that their spores pervade the atmosphere, and are ready, under favouring conditions, to increase and multiply; we know that they are ubiquitous, and that those conditions most favourable to their development, are exactly such as are proved to foster and engender disease, and above all, they have been proved to be the elements of some diseases in man, in animals, and in plants. Can as much be said of any other known agents, animate or inanimate, comprised in our category? It has been said, we do not see after death,—the It is perhaps necessary to say something in explanation of the sudden deaths arising from morbid poisons. They may occur from two causes. One being the result of a concentrated amount of poison germs being inhaled into the lungs, and acting as an ordinary toxic agent; and the other, which I put only hypothetically, the consequence of the rapid evolution of gas in the vessels arising from a sudden decomposition of blood, as it passes through the lungs. The only authority I have for this supposition, is the fact that the blood after death, from pestilential affections, is found to be far advanced towards decomposition; that in Paris last year, two patients were bled while suffering from Cholera, and with the small quantity of blood which flowed, bubbles of air also escaped:[70] and besides this, it was demonstrated by Mr. Herapath, that ammonia was given off from Cholera patients, both by the lungs and skin. These facts, though they are not conclusive, nevertheless render it probable that such an explanation is not entirely out of reason—especially too, when we know how fatal are the effects of uncombined air, when it enters the vessels near to the heart. SECTION III. WHAT RESULTS DO WE OBTAIN FROM THE EFFECTS OF REMEDIAL AGENTS, IN PROOF OF THE HYPOTHESIS? I have here used the word hypothesis, because, having so far advanced in the enquiry, I trust sufficient has been said to render the term applicable. Under the term remedial agents, I shall include all those causes, whether natural or artificial, which tend to neutralize or destroy the germs of infection, or miasmatic poison, whether this be effected out of or within the body. First, then, let us consider the results of drainage and cultivation in removing the causes of endemic disease. One well authenticated case is as good as a thousand. I will take one, which, from its source, will be received as unexceptionable; and from its association with a very learned and amusing book, will be accepted as an agreeable reminder of the many pleasant hours spent in the perusal of the poet Southey's "Doctor." "Doncaster is built upon a peninsula, or ridge of land, about a mile across, having a gentle slope from east to west, and bounded on the west by the river; this ridge is composed of three strata; to wit, of the alluvial soil deposited by the river in former "These fens were drained and enclosed pursuant to an Act of Parliament, which was obtained for that purpose in the year 1766. Three principal drains were then cut, fourteen feet wide, and about four miles long, into which the water was conducted from every part of the Carr southward, to the little river Torne, at Rossington Bridge, whence it flows into the Trent. Before these drainings, the ground was liable to frequent inundations; and about the centre there was a decoy for wild ducks; there is still a deep water there of considerable extent, in which very large pike and eels are found. The soil, which was so boggy at first that horses were lost in attempting to drink at the drains, has been brought I feel certain of being excused for transcribing this long passage from Southey. It would have been impossible to convey its whole meaning without giving it entire. The continuation of the chapter is no less instructive and applicable to our subject, though more particularly so to an extension of the enquiry. The sore throats and intermittents, from which Doncaster has been freed, by the drainage of Potteric Carr, informs us at once that decomposing matter is the material by which the poison of fever is vivified and sustained, the wet and boggy state of the soil is just the condition, when no drainage exists, to bring into activity the germs of Let warmth, moisture, darkness, and decaying matter be given, and inanimate disintegrated particles will soon be converted into definite forms and combinations instinct with life. It is by the unseen forms of living beings, that the atmosphere is preserved from becoming charged with deadly gases; they take the first rank in the great scheme of animated beings, the plant first, and then the animal. "Let the earth bring forth grass." "Let there be lights in the firmament." "Let the waters bring forth the moving creature, and fowl that may fly," and "Let the earth bring forth the cattle, the creeping thing, and the beast." This is the order of creation, of living things, and the earth was prepared by vegetation for the animal world. The work of conversion is accomplished by vegetation; and this is consumed for the construction of higher organizations. The laws which govern and control the universe, Cultivation and drainage are now fully understood to be the basis by which a healthy condition of air is to be obtained, next to that, cleanliness and ventilation; if either be neglected a sickly, mouldy, and unwholesome contamination of atmosphere ensues; the odour of a bog is proverbially mouldy, and so is that of an ill-ventilated house or cellar; dryness, or the fresh pleasant scent of clean water, are the antagonists of these; the aromatic odours of vegetation are opponents of putrefaction, and consequently of the development of the lower forms of life. All empyreumatic matters prevent mouldiness and decomposition; and odours arrest and prevent the growth of mouldiness. The oil of birch, with which the Russia leather is impregnated, and which gives it so pleasant an odour, effectually prevents mouldiness, and consequently decay. Lindley says, "It is a most remarkable circumstance, and one which deserves particular enquiry, that the growth of the minute fungi, which constitute what is called mouldiness, is effectually prevented by any kind of perfume."[71] Cedar has Pitch and tar dealers are everywhere spoken of as being remarkably exempt from infectious diseases. Cold infusion of tar was used in our colonies as a prophylactic against the Small Pox. Bishop Tan yards and places in the immediate vicinity, are said to be free from pestilences. The tanners of Bermondsey are said to have escaped the Plague of London, and one person only died in Gutter Lane, where was a tan yard. The tanners of Rome are also stated to have been free from Plague. Dr. M‘Lean refers to the exemption of tanners at Cairo. Tannin is prejudicial to most vegetables,—but Dr. Lindley says it is not always so to fungi. "A species of Rhizomorpha is often developed in tan pits." I should imagine that neither plants nor insects would be found very abundantly, where tannin prevails; yet we find that the gall-nut is formed for the protection of an insect from injury by weather, and as a temporary means of sustenance. The custom of fumigating with odoriferous substances, does not therefore appear upon this view of the matter to be destitute of importance; indeed, the universal practice stamps it at once, as an efficacious remedy for the purposes of disinfection. The introduction of chlorine fumigation, seems to have superseded, in a great measure, the use of fragrant herbs and woods; and it is questionable whether the substitution be altogether desirable or The fumigations of sulphurous acid and chlorine are, perhaps, more adapted as disinfectants in uninhabited apartments;—their power to destroy vegetation, is well known. They have been used, chiefly, with the idea of neutralizing gaseous exhalations, particularly chlorine, as it tends to combine with hydrogen, to form hydrochloric acid, and then to unite with ammoniacal matters, forming hydrochlorate of ammonia. This, supposing noxious or pestilential effluvia consisted of the ammoniacal exudations variously combined, was an exceedingly efficacious method of rendering them inert; but as we feel convinced that no ammoniacal compound could possibly be the cause of infection, we must look to the influence these gases possess over other forms of matter, and as they are so destructive, even in minute quantities, to vegetable existence, it is possible that their beneficial effects may be due to this property. The immediate neighbourhood of gas works is prejudicial to vegetation, I imagine, from the amount of sulphurous vapours, and to this has been attributed the exemption of persons employed in these works. Many other instances might be cited of a similar nature. I have now to speak of medicinal agents, and here comes a considerable difficulty. If we might believe all that has been written on the sure and certain remedies for the "ills that man is heir to," we should be led to acknowledge that both nature and art were prodigal in antidotes and specifics. The all-bountiful hand of nature, I do not doubt, has at the same time scattered the seeds of good and of evil. The fertilizing showers fall to irrigate the soil, and produce food and nourishment to man; here and there is the reeking morass "feeding unnatural vegetation," and if man takes up his abode in its vicinity, the rains which made it unhealthy, have also made it highly fertile; by labour and cultivation he may convert the mephitic bog into a waving corn-field, and the seeds of life and sustenance be made to supplant the seeds of death and corruption. It is generally believed, that where there are particular and specific diseases, there also may be found appropriate and specific remedies; the discoveries of chemistry, it is not improbable, may in some respects have retarded the progress of natural medicine. In the early ages of the world, the "healing plant" must have formed the staple of medical commerce, for though Tubal Cain[73] has been considered as the first surgical instrument maker, because he was the first artificer in brass and iron, we have not discovered that chemical compounds entered into the composition of physic, till very Of the result obtained by medical treatment, in cases of epidemic or infectious disease, it is most But to the late Epidemic. Dr. Stevens' saline treatment, appears, on the whole, to have been the most successful. Common salt was used both medically and dietetically, and formed the greatest bulk of the medicine employed. Chlorate of potash and carbonate of soda were added to the medicine. The nitro-hydrochloric acid was used with success at St. Thomas's Hospital. Dr. Copland used chlorate of potash, bicarb. soda, hydrochloric, ether, and camphor water. Dr. Ayre's calomel treatment had as many, if Creasote and camphor were lauded by some. The beneficial operation of all these remedies might be explained on the theory here supposed, that living germs are the cause of Epidemic disease, but the specific action of any one remedy has not yet had sufficient attention or trial to enable me to make any deductions of a satisfactory or conclusive nature. In the uncertainty which generally prevailed as to the best method of treating Cholera patients, I was induced (for reasons stated in a pamphlet published last year) to try the efficacy of sulphur, which had been extolled as a specific. In its effects I was not disappointed; but as the results are already before the public, I need not do more than refer to it among other remedies. I did not contemplate even alluding to this subject, as it would extend far beyond my intended limits. This portion of the enquiry would be more properly carried out by keeping records of cases, treated in accordance with the view attempted to be established, and I have not the slightest hesitation in saying, that the most ample success would ultimately attend a well directed practice, based upon the principles inculcated in these pages. In making the foregoing sketch, I have attempted to put together some ideas on a subject, which has for the last few years been a theme for meditation in leisure hours, viz. What are the causes of Epidemic, Endemic, and Infectious Diseases? The occurrence of Epidemic Cholera last year in this country, awakened a spirit of enquiry. Where there is unrest, whatever may be the cause, there also is disquiet and discontent. When the oracles of the age were consulted in the emergency, the discordant answers perplexed and confused the anxious searcher after truth. In the spring of last year, when the enemy was approaching, unseen and unheard, and the thousands of unconscious victims, who are now lying in their graves, were faithfully trusting and fully relying on the heads of our profession, and the resources of our art, what was the state of our defences, and what the nature or character of our resistance? One considerable body of men would discharge from a little tube of glass, a host of almost invisible globular atoms of sugar, said to be as potent and inscrutably operative as the unseen enemy. These infinitesimal practitioners assured the people that they "had powerful means of subduing the disease," Who can deny the force of this observation? Sheltered by a principle, it matters not how fallacious, a man is placed as behind a barrier. If with any reason it could be shewn that the infinitesimal doses, could by no possibility effect a cure in Cholera; if it could be demonstrated by any line of argument, that a poison, a living poison, circulates with the blood, or lodges in the tissues, the homÆopathist must fall; his "electricity and mineral magnetism," and "powerful concentration of life power towards the digestive canal," will stand for what they are worth. That minute doses of medicine can exert an active influence over the body is not to be denied, but these must consist of powerful drugs, as arnica, aconite, and nux vomica, with others, and it is more than probable, that of such medicines, an inconceivably small amount may produce a specific effect upon some portion of the organic nervous system. How is it that a dose of nitre or digitalis, "can Why should indigo dyers become melancholy, and scarlet dyers choleric?[75] We do not know. But there is one thing we most certainly do know, that a poison may be disarmed by an antidote, and the amount of the latter must be in proportion to that of the former, and as epidemic and contagious diseases do most unquestionably depend upon poisons of a specific nature, and of great amount and activity, an infinitesimal remedy, however it may claim to direct and control the organic forces, under slight and ordinary disturbances, can be no more effectual in destroying the poison of fever, or small pox, than in neutralizing arsenic or prussic acid. The uncertainty which generally prevails as to the treatment of Epidemic diseases, Fevers, &c. induced me to put together the notions which are contained in these pages, in the hope of leading to some definite ideas of the causes of these affections, and consequently to a more uniform and scientific mode of treating them. I have endeavoured to shew that reproduction is a phenomenon inseparable from morbific matter, and that in all probability the vegetable kingdom is the source of the germs. The train of argument adopted is such as appeared to me most natural for such an enquiry, and it rests now only with those who are capable of deciding whether such a course, though (I am sensibly aware) not without many faults in conception and execution, is calculated to advance the science of medicine and the interests of mankind. The real tree of knowledge, possesses in the spongioles of its roots, an elective property, by which truth alone can enter; nourished and sustained by this, it sends a fragrant incense and breathing odour on high, and dispels the mists of ignorance and superstition. In natural causes and reasonable deductions we must seek for instruction and solid information, for in over-straining either nature or art, deformity and error must inevitably be the result. THE END.NORMAN AND SKEEN, PRINTERS, MAIDEN LANE, COVENT GARDEN. NOTES[1] "It matters little how vague and false hypotheses may appear at first: experiment will gradually reduce and correct them, and all that is required, is industry to elaborate the proof, and impartiality to secure it from distortion."—Sewell "On the Cultivation of the Intellect." [2] It is stated by Mr. Crosse, of Norwich, that vaccination was adopted in Denmark, and made compulsory in 1800. After the year 1808 Small Pox no longer existed there, and was a thing totally unknown; whereas during the twelve years preceding the introduction of the preventive disease, 5,500 persons died of the Small Pox in Copenhagen alone.—Dr. Watson's Lectures. Dr. Blick, an intelligent Danish physician, corroborated the above statement to Dr. Watson himself in the year 1838. [3] Philosophy of Life, Lecture 6, translated by the Rev. A. J. W. Morrison, M.A. [4] The following I quote from Dr. Fuller on Small Pox and Measles:— "To this purpose some (and particularly Kircherus) are of opinion that animalcules have been the causes of malignant and pestilential fevers in epidemic times, which differ in essence and symptoms, according to the nature and venoms of those creatures. "Thus the atmosphere and air is filled both from above and beneath with innumerable millions of millions of species or corpuscles, aporrhoeas, steams, vapours, fumes, dust, little insects, &c. all which make it such a wonderful chaotic compost of things that contains the seeds of good and evil to man as surpasseth the understanding (as I suppose) of even the highest order of archangels." [5] I learn from an undoubted authority that the cow when "slack of health" eats with avidity the "field parsley;" the sheep under similar circumstances seeks the ivy, and the goat the plantain. From an equally good source I have the following: that rabbits and hares, when they are what is commonly called pot-gutted, seek the green broom, though at a distance of twenty miles. [6] "My settled opinion is, that in regard every effect is necessarily such as its cause; it must needs be that every sort of venomous fevers is produced by its proper and peculiar species of virus. "And that the manner and symptoms of every such fever is not so much from the particular constitution of the sick; as from the different nature and genius of their specific venom which caused them. "And I conceive that venomous febrile matters differ not in degree of intenseness only, but in essence and toto genere also; and that venomous fevers are for the most part contagious."—Thomas Fuller, M. D. 1730. "Another important class of organic poisons are those which when introduced in almost inappreciable quantities into the system, seem to increase in quantity; and which when communicated in the same inappreciable quantity from the individual poisoned to one who is healthy, excite the same series of febrile phenomena and local inflammation, and the same increase in the quantity of the poisonous agent."—Med. Chir. Review. "This unseen influence working in the body, presents very striking analogies to the modes of operation of different poisons."—Dr. Ormerod on Continued Fever. [7] I am aware that the vesicle does not here strictly bear the relation to the original germ, supposing one active particle alone to be sufficient for its production, that the egg does to the bird, for in the former case multitudes of active particles may have been generated from one. I have, therefore, merely used this expression to signify an aggregation of vital forces, such as may be imagined to exist in the bird. [8] "At an early period the form of the ovisacs is usually elliptical, and their size extremely minute,—their long diameter measuring in the ox no more than 1/562 of an inch, so that a cubic inch would contain nearly two hundred millions of them. They are at this time quite distinct from the stroma of the ovarium; this forms a cavity in which they are loosely embedded." [9] Coleridge, p. 56. [10] "All vegetables," says Sharon Turner, "from that pettiness which escapes our natural sight, to that magnitude which we feel to be gigantic, have these properties in common with all animals—organization; an interior power of progressive growth, a principle of life, with many phenomena that resemble irritability, excitability, and susceptibility, and a self-reproductive and multiplying faculty."—Sharon Turner's Sacred History. [11] "Plants highly sensitive to light are those of the leguminous, or Pea kind. They always close up in the evening and clasp their two upper surfaces together, presenting only their backs to the air. Plants of pinnated leaves, as the Tansy, are more sensible than these to the effects of light. They fold up when light is too strong, as in Robinia; it produces the same effect as want of light. Its leaves close up, apparently, because they are receiving too much. So they do if a hot iron be brought near them. They contract as if to avoid the heat. Sensitive plants, and those of the Oxalis Lent. are so sensitive that the least motion, even a breath of air, will make them close."—Sir J. Smith. "The vitality of plants seems to depend upon the existence of an irritability, which although far inferior to that of animals, is nevertheless of an analogous character."—Lindley's Introduction to Botany. [12] Provincial Medical and Surgical Journal. July 10th, 1850. No. xiv. p. 367. "Practical Observations on the Vaccination Question." By E. Oke Spooner, M. R. C. S., Blandford. "If we examine the Cow Pox and the Small Pox microscopically, as I have done very carefully in every stage, we find that the essential character consists of a number of minute cells, not exceeding the 10,000th part of an inch in diameter, being about one-fourth smaller than the globules of the blood, containing within their circumference many still more minute nuclei, and presenting beyond their circumference bud-like cells of the same size and character as those contained within the circle. They exactly resemble in everything except the size, the globules of the yeast plant, the Torula CerevesiÆ. Now if we examine more circumstantially the analogies of what I would call the Torula VariolÆ with the Torula CerevesiÆ, we observe the following corresponding facts. "What do we accomplish by inoculation as it is called? Simply this. We take on the top of a lancet, or an ivory point, a few of these minute cells or germs, and we put them in their appropriate nidus, the subcuticular tissue, where, after a few days if they find their appropriate nutrient elements, they grow and multiply." Simon, Chemistry of Man, vol. i. p. 127. "Macgregor ascertained that the air expired by persons ill of confluent Small Pox, contained as much as eight per cent of carbonic acid, and in proportion as health was restored the percentage was diminished to its natural standard." Carbonic acid is also produced during the process of fermentation and germination. [13] See History of the Jews, p. 71. [14] It is said by Whewell, that the murrain is supposed to have fallen only on the animals which were in the open pasture.—History of the Jews. "J. S. Michael Leger, published at Vienna, in 1775, a treatise concerning the mildew as the principal cause of the epidemic disease among cattle. The mildew is that which burns and dries the grass and leaves. It is observed early in the morning, particularly after thunder-storms. Its poisonous quality, which does not last above twenty-four hours, never operates but when it is swallowed immediately after its falling."—Mitchell on Fevers. [15] "The prevalence of the south-east wind was observed to be particularly favourable to the increase of both cholera and influenza: and I cannot but think that this had some connexion with the general tendency exhibited by the former to spread from east to west. Has the morbific property of this wind aught to do with the haziness of the air when it prevails—a haziness seen in the country remote from smoke, and quite distinct from fog? What is this haze? In the west of England a hazy day in spring is called a blight."—Dr. Williams' Principles of Medicine. [16] We are to understand also that some peculiar operation took place of a nature difficult to comprehend, which seems also to typify reproduction, for the handfuls of ashes which Moses threw into the air became a dust in all the land of Egypt, thus signifying an enormous reproduction of atomic matter. [17] The Chinese affect to trace the origin of Small Pox back to a period of at least 3000 years, or 20 years beyond the era of the Trojan war, 1212, A. C. The Chinese pretend to discriminate no less than 40 different species of Small Pox. "They also pretend to discover whether a person has died by violence or from natural causes, not only after the body has been some time interred and decomposition of the softer parts has commenced, but even after the total disappearance of the soft parts, and when the dry skeleton alone is left."—For the process, see Hamilton's History of Medicine, vol. i. p. 31. To give some notion of the state of Medical Science among the Chinese, I may quote the following: "The theory of the circulation of the blood, Du Halde affirms, was known by the Chinese about 400 years after the deluge; be this assertion veracious or not, no correct knowledge up to the present day, do the nation possess of the circulating system of the human frame."—China and the Chinese, Henry Charles Sirr, M. A. According to their anatomy, the trachea extends from the larynx through the lungs to the heart, whilst the oesophagus goes over them to the stomach. [18] "And Aaron took as Moses commanded, and ran into the midst of the congregation: and behold the plague was begun among the people; and he put on incense and made an atonement for the people. And he stood between the dead and the living, and the plague was stayed."—Numbers. The practice of burning scented herbs has been observed in all times during an invasion of the plague, as a means of protection. Also wearing perfumes and aromatic preparations has been recommended. Whether they have any counteracting influence, it is impossible to say. Virgil in the third Georgic speaks of a murrain among cattle. He says, if any wore a vestment made of wool from an infected sheep, fiery blains and filthy sweat overspread his body, and ere long a pestilential fire preyed upon his infected limbs. In his directions for preserving the health of flocks he says— "Disce et odoratam stabulis accendere cedrum." The motive for burning the fragrant cedar is not mentioned; we cannot doubt but it was a good one, and having some great practical utility, from the following line— "Galbaneoque agitare graves nidore chelydros." [19] The earliest mention of this complaint upon which reliance can be placed, is an ancient Arabic MS. preserved in the public library at Leyden. "This year, in fine, the Small Pox and Measles made their first appearance in Arabia." The year alluded to being that of the birth of Mahomet, or the year 572 of the Christian Æra.—Hamilton's History of Medicine, vol. i. p. 215. [20] Dr. W. A. Greenhill's translation. [21] The Black Assize at Oxford, 1572, is an instance in which a pestilential vapour suddenly appeared in the court, "whereby the judge, several noblemen, and more than 300 others, died within three days." "Of an unaccountable vapour suddenly coming, I have this relation from Richard Humphrey, my neighbour, and a man of veracity, that on Wednesday, April 27, 1727, as he and one Walter, were travelling a-foot from Canterbury; when they came to Rainham, they were assaulted with such a strong loathsome stink, as he thought was like the stench from a corrupted human corpse. They were so offended at it, as thinking it was from carrion in that town, that they would not stay there to rest and refresh themselves, but travelled on for about two hours, mostly in the stench, but sometimes out of it, till they came to the hill that leads down to Chatham: and there they went clear out of it and smelt it no more."—Dr. Fuller. It appears that these persons did not fall sick of any disease, but the fact of itself is remarkable enough. [22] Hamilton's History of Medicine. [23] It has been said, that "an induction once carefully drawn, is as perfect from a single instance as it is from ten thousand, and that it is only an uncultivated mind which requires a load and accumulation of knowledge to assist his thoughts."—Sewell "on the Cultivation of the Intellect." [24] See Dr. Alison's Pamphlet on the Fever in Edinburgh. [25] Earthquakes have in all times been considered to have some connexion with pestilences. "A most grievous pestilence broke out in Seleucia, which from thence to Parthia, Greece, and Italy, spread itself through a great part of the world, from the opening of an ancient vault in the temple of Apollo, and that it raged with so much fury as to sweep away a third part of the inhabitants of those countries it visited."—Dr. Quincy, on the Causes of Pestilential Disease. "Upon an earthquake the earth sends forth noisome vapours which infect the air; so it was observed to be at Hull in Yorkshire, by the Rev. Mr. Banks, of that place, after a small earthquake there in 1703, it was a most sickly time for a considerable while afterwards, and the greatest mortality that had been known for fifteen years."—Anonymous, 1769. [26] See Sharon Turner's Sacred History, text and notes, vol. i. p. 161 & 162. [27] "Each seed includes a plant; that plant, again, Has other seeds, which other plants contain, Those other plants have all their seeds; and those More plants, again, successively enclose. Thus ev'ry single berry that we find, Has really in itself whole forests of its kind. Empire and wealth one acorn may dispense, By fleets to sail a thousand ages hence; Each myrtle-seed includes a thousand groves, Where future bards may warble forth their loves." [28] "On June 5th, 1849, a man and his son, a lad aged 14 years, left Noss to fish, and when five miles out at sea, no vessel being in sight, they both simultaneously became aware of a hot offensive stream of air passing over them. It was so decided, that the crab pots were examined to discover if it were from them, but it did not, and five minutes after the father's attention was directed to the boy, who was vomiting and purging."—Dr. Roe on the Cholera at Plymouth, Med. Gaz. Aug. 24th, 1850. [29] LinnÆus remarked that Erigeron Canadense was introduced into gardens near Paris from North America. The seeds had been carried by the wind, and this plant was in the course of a century spread over all France, Italy, Sicily and Belgium. [30] Hecker. [31] This is found most generally to be the case where rivers flow through uncultivated tracts of country. The Californian emigrants suffer much from diarrhoea and dysentery, if they drink of the river and certain well waters of that gold district. [32] "Purification from leprosy. As this fearful disease was contagious and hereditary to the third and fourth generation, the separation of lepers from the camp and congregation, and the destruction of infected houses and clothes, was of the utmost importance to the preservation of public health. "Leprosy was of three kinds: 1st, Leprosy in man. 2nd, Leprosy in houses. 3rd, Leprosy in clothes. "Contagious or malignant leprosy was of two kinds, viz. "1st. The white leprosy, or bright berat, which was the most serious and obstinate form which leprosy assumes. It exhibited itself as a bright white and spreading scale, on an elevated base; turning the hair white in patches, which were continually spreading. "2nd. The black leprosy, or dusky berat, which was less serious than the foregoing. It did not change the colour of the hair, nor was there any depression in the dusky spot; but the patches were perpetually spreading, as in the white leprosy."—Analysis and Summary of Old Testament History. Oxford. [33] The Mexican Aloe blows when nine years old, and then dies. At least this is its usual course in the island of Cuba. [34] "Ground that has not been disturbed for some hundred years, on being ploughed, has frequently surprised the cultivator by the appearance of plants which he never sowed, and often which were then unknown to the country. The principle has been ascertained to be capable of existing in this latent state for above 2000 years, unextinguished, and springing again into active vegetation, as soon as planted in a congenial soil. "In boring for water near Kingston on Thames, some earth was brought up from a depth of 360 feet, and though carefully covered with a hand-glass to prevent the possibility of other seeds being deposited on it, was yet in a short time covered with vegetation. "Turner says, from the depth, these seeds must have been of the diluvian age."—Jesse's Gleanings. [35] Hamilton's History of Medicine, vol. ii. p. 276, note. [36] "What I wish you to remark is this, that while almost all men are prone to take the disorder, large portions of the world have remained for centuries entirely exempt from it, until at length it was imported, and that then it infallibly diffused and established itself in those parts."—Dr. Watson on the Principles and Practice of Physic. Dr. R. Williams says, "The seeds of intermittent fever lay dormant for months, it was not at all uncommon for cases of intermittent fever to be brought into the hospital eight or ten months after the patients had subjected themselves to the influence of paludal or marsh effluvia." [37] I have observed in the hot-houses, that many of the exotic plants, which are in company with the diseased vines, have been attacked, while others again have been entirely free. [38] By causes of the greatest variety plants may become extinct for a time. It is not very easy to trace them, but one fact may be mentioned in proof of the statement. Dr. Prichard states that vast forests are destroyed either for the purpose of tillage or accidentally by conflagrations. "The same trees do not reappear in the same spots, but they have successors, which seem regularly to take their place. Thus the pine forests of North America when burnt, afford room to forests of oak trees." [39] Hecker says of Chalin de Vinario, that "he asserted boldly and with truth, that all epidemic diseases might become contagious, and all fevers epidemic,—which attentive observers of all subsequent ages have confirmed." P. 60. [40] In 1539, the thirty-first year of Henry the Eighth, was great death of burning agues and flixes; and such a drought that welles and small rivers were dryed up, and many cattle dyed for lacke of water; the salt water flowed above London Bridge.—Stowe. In 1556, the fourth of Mary, and the third of Philip, about this time began the burning fevers, quarterne agues, and other strange diseases, whereof died many.—Stowe. The next winter, 1557, the quarterne agues continued in like manner, or more vehemently than they had done the last yere.—Stowe. [41] Every writer on the climate of Egypt has remarked, that the Endemic Fever which is so frequent, originating on the coast, particularly about Alexandria, becomes occasionally so virulent, that it cannot be distinguished from the true Plague.—Robertson on the Atmosphere, vol. 2. p. 384. "Endemial Fevers of every situation become occasionally so aggravated, that they cannot be distinguished from such as originate from contagion; and in every unusual virulence of this Endemic Fever, it is probable that it may be propagated afterwards by contagion as every epidemic." Ibid. p. 388. [42] Dr. Ure. [43] "The metamorphosis of starch into sugar depends simply, as is proved by analysis, on the addition of the elements of water. All the carbon of the starch is found in the sugar; none of its elements have been separated, and except the elements of water, no foreign element has been added to it in this transformation."—Liebig, Organic Chemistry, p. 71. [44] As regards starch there appears to be some peculiar faculty regarding it. It is converted into sugar during the ripening of fruit, and it is just possible that being as it is of a cellular nature, the property of vitality may attach to it until it has, by being converted into sugar, fulfilled its destination. [45] Though I do not consider that the fermentation process is a fac-simile of diseased action, yet I think its phenomena generally afford an apt illustration of the changes which may be effected by living germs. Many able chemists still maintain the entire dependence of fermentation upon the Torula: "M. Blondeau propounds the view that every kind of fermentation is caused by the development of fungi." The varieties of opinions found in the literature of this subject, forms a curious specimen of scientific enquiry, and is sufficient alone to convince us of its vast importance and extensive relations. [46] By Dr. Mantell. [47] Mitchell on Fevers. [48] We wonder, and ask ourselves: "What does SMALL mean in Nature?"—Schleiden's Lectures on Botany. [49] Speaking of the bunt in wheat: "It appears certainly to be contagious, from numerous experiments, which shew that the contagious principle lasts a long time. I have tried it myself; some, however, doubt it, but it cannot be denied, that seed sown, infected with bunt, produces plants similarly affected; every one who has had the slightest experience must be convinced of it."—Essay on the Diseases of Plants. Count RÉ. [50] We have already spoken of the effects of these poisons, and have stated that the amount of each poison capable of destroying the body is pretty accurately known. [51] The italics are my own. [52] Gmelin says: "But the mode of action in these transformations, sometimes admits of other explanations; and when this is not the case, our conception of it is by no means sufficiently clear to justify the positive assumption of this, so called contact-action or catalytic force, which, after all, merely states the fact without explaining it"—Gmelin's Hand-book of Chemistry, vol. i. p. 115. [53] The history and symptoms of some epidemic diseases, such as cholera and influenza, are not inconsistent with the hypothesis that they are caused by the sudden development of animalcules from ova in the blood. But there is a total want of direct observation in support of this hypothesis.—Dr. Williams' Principles of Medicine. [54] Since writing the above, I have referred for information on this subject, and find, that the Anguillula aceti exhibits sexual distinctions; and that the ovaries of the females are situated on each side of the alimentary canal.—Cyclo. Anat. and Phys. Art. Entozoa. [55] Speaking of the examination of the infusory animalcules—Mr. Kirby says: "But to us the wondrous spectacle is seen, and known only in part; for those that still escape all our methods of assisting sight, and remain members of the invisible world, may probably far exceed those that we know."—Bridgewater Treatise, vol. i. p. 158. [56] Mr. Owen has added another class, as the first, called Protelmintha, which comprises the cercariadÆ and vibrionidÆ. [57] "It is probable that in the waters of our globe an infinity of animal and vegetable molecules are suspended, that are too minute to form the food of even the lowest and minute animals of the visible creation: and therefore an infinite host of invisibles was necessary to remove them as nuisances."—Bridgewater Treatise, vol. i. p. 159. "When Creative Wisdom covered the earth with plants, and peopled it with animals, He laid the foundations of the vegetable and animal kingdoms with such as were most easily convertible into nutriment for the tribes immediately above them. The first plants, and the first animals, are scarcely more than animated molecules,* and appear analogues of each other; and those above them in each kingdom represent jointed fibrils."†—Bridgewater Treatise, vol. i. p. 162. * Globulina and Monus. † Oscillatoria and Vibrio. [58] "A treatise which should present a systematic arrangement of all the diseases of plants, giving in detail the exact history of each, and adding the means of preventing and curing them, would certainly be of the greatest utility to agriculture." —Essay on the Diseases of Plants, Count Philippo RÉ, translated into Gardener's Chron. [59] "Plenck published a treatise on Vegetable Pathology, in which he divided diseases into eight classes: 1. External injuries; 2. Flux of juices; 3. Debility; 4. Cachexies; 5. Putrefactions; 6. Excrescences; 7. Monstrosities; and 8. Sterility. And he concludes with an enumeration of the animals which injure plants."—Essay on the Diseases of Plants, Gardener's Chronicle. [60] The Bunt. "This disease appears at the moment of the germination of the plant. The affected individuals are of a dark green, and the stem is discoloured. As the ears are issuing from the sheaths, their stalks are of a dark green, but very slender. When the ear has fully grown out, its dull, dirty colour, causes it to be immediately distinguished from the healthy ones, and it soon turns white."—Essay on the Diseases of Plants. [61] Vidi understood. [62] "At the close of the year 1665," says Dr. Hodges, "even women, before deemed barren, were said to prove prolific." "After the cessation of the Black Plague, a greater fecundity in women was every where remarkable—a grand phenomenon, which from its occurrence after every destructive pestilence proves to conviction, if any occurrence can do so, the prevalence of a higher power in the direction of general organic life. Marriages were almost without exception prolific; and double and treble births were more frequent than at other times."—Hecker, p. 31. [63] It is stated that on the decline of the Plague, 1665, those who returned early to London, or new comers, were certain to be attacked. In proof of this the 1st week of November, the deaths increased 400, and "physicians reported that above 3000 fell sick that week, mostly new comers." See also Dr. Copland's Dict. Pract. Med. Epidemic and Endemic Diseases. "The hardy mountaineer is a surer victim of paludal fever, whether he visits the low countries of the tropics, or the marshes of a more temperate climate, than the feebler native of those countries."—Dr. R. Williams on Morbid Poisons. [64] "Substances presented to the gastro-intestinal surfaces, are mixed up with various secretions, mucus, saliva, gastric juice, bile, pancreatic liquor, and special exudations from the peculiar glands of each successive section, while aerial poisons, unmixed and unfettered, are applied at once to a surface on which, behind scarcely a shadow of a film, circulates the blood prepared, by the habitual action of the respiratory function, to absorb almost every vapour, and every odour, which may not be too irritating to pass the gates of the glottis."—Mitchell on Fevers. [65] Hecker on the "Black Death." [66] The stomach in some cases is no doubt the medium by which some diseases are contracted. It is well known, that in many places the water induces diarrhoea, the permanent residents, however, may not suffer, but all new comers are more or less affected by drinking it. [67] "Similar effects have been experienced from the use of mouldy provisions."—Dr. Lindley's Vegetable Kingdom. [68] "Untold numbers die of the diseases produced by scanty and unwholesome food."—Southey. A large, nay, a most extensive adulteration of flour with plaster of Paris was detected not many years since. The flour was supplied by a contractor for the manufacture of biscuits for the navy. [69] See Southey's Doctor, vol. ii. interchapter vi. p. 115, for an illustration of this subject. [70] Both these patients died. [71] "A good part of the clove trees which grew so plentifully in the island of Ternate, being felled at the solicitation of the Dutch, in order to heighten the price of that fruit, such a change ensued in the air, as shewed the salutary effect of the effluvia of clove trees and their blossoms; the whole island, soon after they were cut down, becoming exceeding sickly." [72] The observation is originally taken from the City Remembrancer, 133. [73] See Hamilton's History of Medicine, vol. i. p. 4. [74] Feuchtersleben's Medical Psychology, p. 176, 177. [75] Ibid. p. 321. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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