 
Medicinal Substances are those bodies, which, by due administration, are capable of producing certain changes in the condition of the living system, whereby its morbid actions may be entirely removed, or advantageously controlled. In adopting this definition we intentionally exclude those alimentary substances which are more immediately subservient to the support of life, and to the repair of that diurnal waste, which the exercise of its functions so inevitably occasions. It has been generally supposed, that substances whose application does not produce any sensible action upon the healthy system, cannot possess medicinal energy; and, on the contrary, that those bodies which occasion an apparent effect in health, must necessarily prove active in the cure or palliation of disease. Under certain limitations we may perhaps venture to assent to this general proposition; but it cannot be too forcibly or too frequently impressed upon the mind of the medical practitioner, that Medicines are frequently but relative agents, producing their effects in reference only to the state of the living frame; we must therefore concur with Sir Gilbert Blane in stating, that the virtues of Medicines cannot be fairly essayed, nor beneficially ascertained, by trying their effects on sound subjects, because that particular morbid condition does not exist which they may be exclusively calculated to remove; The Modus Operandi of remedies, or the general principle upon which they effect salutary changes in the morbid states of the body, is involved in considerable obscurity, and has given rise to much ingenious That certain bodies are capable of evading the assimilating functions, and of entering, unchanged, into the circulating current, either through the branches of the thoracic duct, or of the vena portarum, is a fact which admits of chemical demonstration; many of the alkaline salts are thus conveyed to the kidneys, and being excreted from the blood by its vessels, are to be easily detected in the urine by appropriate reagents; I have made many experiments upon this subject, and am prepared to state some results which may perhaps explain the occasional value of such bodies as medicines. Some essential oils, particular bitter principles, In some instances, the medicinal body undergoes a partial decomposition by the digestive organs, in transitu, by which some of its constituents escape into the circulation, while the others are completely digested, and converted into chyle; this occurs with saline compounds into which vegetable acids enter as constituents. See PotassÆ Acetas. It is also stated That an impression made upon the stomach by a medicinal agent, should be the means of exciting an action in the distant parts of the machine, will not appear extraordinary when we consider how universal a sympathy and control this central organ exercises over every function of the body; imbued with exquisite and diversified sensibilities,—subjected to the first and coarsest impressions of our various ingesta,—stretched occasionally to an enormous extent by the unrestricted indulgence of appetite,—disturbed by the passions,—exhausted by volition, and debilitated by intense thinking; in short, assailed by numerous foes from without, and harassed by various revolutions from within, can we feel surprised that the aberrations of this viscus should give origin to the greater number of maladies with which we are afflicted, or that those medicinal applications should be effective that are directed for their cure, through the medium of its sympathies? A dose of Ipecacuan, by exciting the stomach, will abate both the force and velocity of the heart in its vital motion, and affect the whole series of blood vessels, from their origin to their most minute ramifications, as is evinced by the pallor of the skin under its operation, as well as by its efficacy in arresting hemorrhage; so the brain, when disordered by vertigo, frequently derives instantaneous relief from the administration of a tea-spoonful of Æther in a glass of water. The stomach however is not in every case the medium of sympathy; a substance may excite a powerful impression upon a distant part, by the instrumentality of the nerves, without any concurrence of the stomach; thus, the Belladonna, by coming in contact with the Tunica Conjunctiva of the eye, will occasion immediate dilatation of the Iris, although no other part of the system is in the slightest degree affected. But there is yet another mode by which remedies may be made to exert a sanative effect upon particular organs of the body, through the medium of what Mr. Hunter called contiguous sympathy, and whose existence With respect to the Modus Operandi of medicines the following classification may be established.
And it is important to observe, that these are frequently antagonist operations, and consequently, that remedies, although they should occasion the same apparent effects, unless they act through the same medium, are not SIMILAR agents, but on the contrary, are generally medicinally incompatible with each other; for an illustration of this truth, the practitioner may refer to the observations which I have offered under the history of diuretics. The difficulty of justly appreciating these phenomena, in every instance, has furnished a powerful objection against the validity of any classification of medicinal substances which is founded on their supposed modes of operation; and it must be acknowledged that, if we are unable to assign to remedies their primary action, or to distinguish this from their more obvious, though perhaps secondary effects, we shall frequently be It is probable that, in philosophical strictness, no two medicines in our Materia Medica are perfectly similar, although they recede from each other by such insensible shades of gradation that we may with practical advantage admit their parallelism; at the same time, it must be ever kept in remembrance, that those Medicines only are practically similar, whose operations have been found by experience to continue similar under every condition of the human body; and which, moreover, owe such similarity to modes of operation which are compatible with each other, and consonant with the general indications of cure. The importance of admitting this proposition will be frequently illustrated in the sequel; and it may be observed in this place, that every classification in which it is not recognised as a leading principle, must be as imperfect in its execution, as it will be unjust and erroneous in its views. Before I proceed to any farther discussion upon the present subject, it will be necessary to offer a synoptical view of an arrangement of medicinal bodies founded upon the basis of their operations, in order that I may be better enabled to illustrate the observations which it is my intention to introduce: for this purpose I shall present the reader with three different classifications of this kind; the first being that proposed by Dr. Cullen, CULLEN’S ARRANGEMENT OF THE MATERIA MEDICA.
CLASSIFICATION OF THE MATERIA MEDICA | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| I. | Chemical Agents. | ||
| 1. | Caustics. | ||
| 2. | Antiseptics. | ||
| 3. | Antidotes. | ||
| 4. | Demulcents. | ||
| 5. | Diluents. | ||
| II. | Vital Agents. | ||
| A. Supporting Strength. | |||
| 1. | Nutrients. | ||
| B. Causing Action. | |||
| Partial & Transient. | 1. | Expergefacients. | |
| 2. | Excitants. | ||
| 3. | Calefacients. | ||
| 4. | Sudorifics. | ||
| 5. | Errhines. | ||
| 6. | Sialogogues. | ||
| 7. | Expectorants. | ||
| 8. | Stomachics. | ||
| 9. | Emetics. | ||
| 10. | Cathartics. | ||
| 11. | Chologogues. | ||
| 12. | Hydrogogues. | ||
| 13. | Simply Propellents. | ||
| 14. | Anthelmintics. | ||
| 15. | Diuretics. | ||
| 16. | Carminatives. | ||
| 17. | Emmenagogues. | ||
| 18. | Epispastics. | ||
| 19. | Suppuratories. | ||
| 20. | Sorbefacients. | ||
| 21. | Astringents. | ||
| Permanent. | Tonics. | ||
| C. Diminishing Action or Sensation. | |||
| Primarily | 1. | Narcotics. | |
| 2. | Sedatives. | ||
| 3. | Nauseants. | ||
| 4. | Diaphoretics. | ||
| Secondarily | Exhaurients. | ||
| III. | Insensible Agents. | ||
| Specifics. | |||
CLASSIFICATION OF REMEDIES BY Dr. MURRAY.
| A. General Stimulants. | |
| a. Diffusible. { | Narcotics. |
| Antispasmodics. | |
| b. Permanent. { | Tonics. |
| Astringents. | |
| B. Local Stimulants. | |
| Emetics. | |
| Cathartics. | |
| Emmenagogues. | |
| Diuretics. | |
| Diaphoretics. | |
| Expectorants. | |
| Sialogogues. | |
| Errhines. | |
| Epispastics. | |
| C. Chemical Remedies. | |
| Refrigerants. | |
| Antacids. | |
| Lithontriptics. | |
| Escharotics. | |
| D. Mechanical Remedies. | |
| Anthelmintics. | |
| Demulcents. | |
| Diluents. | |
| Emollients. | |
With respect to the classification of Dr. Cullen, we may commence our objections by stating, that the very basis upon which it rests is a mere gratuitous assumption, viz. that certain medicines act on the fluids of the body. With the exception of a very few substances, it is now generally admitted that medicines produce their effects by acting on the living materials of which our organs are composed, and not by modifying the specific gravity, or chemical composition, of the fluids which they may happen to evacuate. The origin of this latter opinion is to be traced to the exploded notions of the humoral pathologists, and to the exclusive doctrine of the earlier chemists; for as the former recognised a depraved condition of the fluids as the source of every disease, so did the latter imagine that every remedy operated by producing a chemical change upon its composition; and the remedial value of a medicinal substance was estimated by its effects upon inert matter. Thus were experiments made with different substances upon the blood, and other fluids of the body, in order to deduce, from the results, the nature and extent of their powers as agents upon the living frame; for instance, the spirit and salt of hartshorn, as they were found to render the blood more fluid, when added to it, out of the body,
Nor is the distinction assumed by Dr. Cullen, between the action of remedies on the Simple and Living solids less hypothetical. Tonics and astringents may certainly exert a beneficial effect upon the animal fibre, but not by any immediate action on its materials, but through the agency of its living principle.—“Medicamentum non agit in cadaver.”
The classification of Dr. Young, although it presents many points of interest and value, is not altogether free from objection; his classes in some instances are perhaps unnecessarily sub-divided, without a sufficient regard to the primary and secondary operations of the substances which they include. The arrangement of Murray has been adopted in the present inquiry, not as being less objectionable, in a general point of view, but as one which from its simplicity, is better calculated, as a frame-work, if I may so express myself, for the display of those particular facts, the knowledge of which I consider essential for the successful administration of medicinal agents, and for the full comprehension of those practical doctrines which it is the exclusive object of this work to inculcate.
Dr. Murray observes that, in this arrangement, he places in the first division those substances which exert a GENERAL STIMULANT operation on the system. Of this there are two sub-divisions, the Diffusible and the Permanent; the former including the class of Narcotics, with which may be associated, as not very remote in their operation, the class of Antispasmodics; the latter comprising two classes, viz. Tonics and Astringents. Through these there is a gradual transition from the most highly diffusible stimulant, to those most slow and durable in their action.
A second division comprehends Local Stimulants, those, the action of which is determined to particular parts of the system. Such are the classes of Emetics, Cathartics, Emmenagogues, Diuretics, Diaphoretics, Expectorants, and Sialogogues; with which may be associated the classes of Errhines and of Epispastics, founded on direct local application.
The remaining classes include substances which do not operate according to laws peculiar to the living system. To one division may be referred those, whose effects depend on the Chemical changes they produce in the fluids or solids; the classes which may be established on this principle are Refrigerants, Antacids, Lithonthriptics, and Escharotics. To another division belong those, the operation of which is purely Mechanical, as Anthelmintics, Demulcents, Diluents, Emollients, and certain Laxatives.
Under the above classes, says Dr. Murray,
1. GENERAL STIMULANTS.
The four classes comprehended under this first division, are Narcotics, Antispasmodics, Tonics, and Astringents.
Although these remedies differ very essentially in the degree and permanence of their action, as well as in the character of their apparent effects, yet, as it is conceived that their primary operation is stimulant, they are considered as possessing sufficient general similitude to sanction their arrangement under one comprehensive division.
NARCOTICS.
Substances which, in a moderate dose, occasion a temporary increase of the actions of the nervous and vascular systems, but which is followed by a greater depression of the vital powers than is commensurate with the degree of previous excitement, and which is generally followed by sleep.
The relative intensity of these primary and secondary effects varies in the different narcotics,
From the celerity with which narcotics produce their effects, it is reasonable to suppose that they act upon the nervous system through the sympathetic relations of the stomach, although in some instances it is highly probable that these bodies are actually absorbed into the circulation; I am inclined to think that this occurs with opium, as death is accelerated in cases of persons poisoned by it, by the adoption of those measures which are best calculated to promote its absorption: (see Opium.) A still more striking proof is furnished by the fact of opium, when externally applied to ulcers, producing all its constitutional effects, such as costiveness, head-ache, nausea, &c. Whether the effects of spirituous potations are to be attributed to the introduction of alcohol into the blood, or to the sympathies existing between the stomach and brain, is still a question of doubt. Dr. Cooke
At one period, substances supposed to possess narcotic virtues were placed about the bed to obviate watchfulness; the plant Anethum, or Dill, was very commonly suspended over the head for such a purpose, while in modern times the Hop has been introduced into the pillow.
In concluding the history of Narcotics, it may be observed, that there is, perhaps, no class of medicinal bodies, the individuals of which are less disposed to bend and conform to an artificial arrangement; each would seem to have its own particular mode of operation, and to affect sensibility in its own peculiar manner; and hence the practitioner will often find that, after the failure of one narcotic, the administration of another will induce sleep.
ANTISPASMODICS.
Substances which have the power of allaying the inordinate action of muscular structures, and of assuaging pain, without occasioning that state of insensibility which characterises the operation of narcotics.
There are certain medicinal bodies which would appear to exert a specific control over spasmodic action, from whatever cause it may have originated, such are Assafoetida, Galbanum, Musk, Castor, Ammonia, Valerian, &c. To such remedies the term antispasmodic more exclusively belongs, but in a more general view of the subject we must admit that this class branches, by indefinable gradations, into narcotics and tonics; for since spasm may be connected with the most opposite states of the body, it is very evident that many of the individuals included in the class of antispasmodics, can only be relative agents: spasm, for instance, may arise from excessive irritability, as from teething, wounds, worms, &c. in which case a narcotic would prove beneficial; or it may depend upon a state of general debility, the proper remedy for which would be the administration of an Aromatic Stimulant, or the assiduous exhibition of some permanent tonic.
TONICS.
Substances, whose continued administration gives strength and vigour to the body.
It is very justly admitted, that a state of permanent tension in the fibres of the body is necessary for the existence of life, and that any undue departure from such a condition is followed by debility. Thus, Sir Gilbert Blane observes, that no muscle, whether voluntary or involuntary, can act unless its fibres are previously in such a state, that if divided they would shrink by their own resiliency, leaving an interval between the cut extremities; the same may be said of the vascular system in all its ramifications, in order to give play to their contraction in grasping and propelling their contained fluids. It appears that there are certain medicinal bodies that have the power of affecting this state of tension, and when their effects contribute to its restoration, they are properly denominated Tonics. We are not, however, to consider them as producing such a change by any mechanical operation upon the matter of which the fibre is composed, but by a direct action upon its living principle; it seems probable that certain poisons may thus produce sudden death by their agency on the vital principle, by which the tension of the heart and whole arterial system is immediately relaxed. In this point of view, Tonics, like the other remedies which we have described, may be relative or absolute in their operation. Venesection, purgation, or whatever will, under certain conditions of the body, occasion a salutary change in its vital powers, may produce a corresponding alteration in the tension of its fibres, and consequently fall under the denomination of a tonic remedy: but independent of the state of the body, there would seem to be certain substances that act as specific stimuli upon the living fibre, and are in certain cases indispensable for the maintenance of its healthy tone; such are vegetable bitters, which produce a powerful effect upon the digestive organs, and by nervous sympathy,
I have offered these views upon the subject of Bitter Extractive, from a conviction that they will essentially contribute to the establishing of just and philosophical notions, respecting the necessity and modus operandi of many vegetable tonics.
As the action of tonics is gradual, so their operation is not followed by that exhaustion consequent upon the use of diffusible stimulants.
The substances which compose the class of tonics are derived from the vegetable and mineral kingdoms; those of the former are generally bitter, and produce their effects by a primary action on the stomach, and are not absorbed into the circulation, as experiments upon Bitter Extractive have most fully demonstrated; those derived from the mineral kingdom, comprehending several of the metals, appear in some instances to pass into the circulation, although several of them, like the vegetable tonics, act primarily on the primÆ viÆ; I apprehend this observation applies to the nitrate of silver, which certainly possesses considerable powers as a tonic in certain cases of dyspepsia, for which it may perhaps be indebted to the bitterness which distinguishes it.
Substances of a fragrant smell,
The vegetable bodies which constitute the class of aromatic stimulants are very intimately related with that of tonics; indeed in the most efficient vegetables of the latter kind, the two qualities are generally blended, and the transition from these to the more pure bitters and aromatics is so imperceptible, that it is extremely difficult to arrange them in different classes; Dr. Murray has accordingly in his classification not attempted to separate substances which are so intimately connected. Aromatic Stimulants, however, in a practical point of view, must be distinguished from tonics, as the former are valuable for the rapidity, the latter, for the permanency of their effects. Their characteristic properties appear to depend chiefly, if not entirely, on an essential oil which, when extracted from the vegetable, exhibits all its aromatic power in a very concentrated form.
Medicines of this kind, when administered for the purpose of dispelling wind from the alimentary canal, have been termed Carminatives.
ASTRINGENTS.
Substances which, when applied to the human body, corrugate and condense its fibres, and at the same time, exert a tonic influence through the medium of its living principle.
Astringency in any substance may be at once recognised by the organs of taste; its power in corrugating the papillÆ of the tongue, and in imparting a sensation of harshness and roughness to the palate, being too peculiar to be mistaken; this is a fortunate circumstance, for there does not exist any one chemical test by which we can invariably detect the property of astringency, since it is found to reside in many different classes of substances: thus, acids, especially the stronger mineral ones, are powerfully astringent; so are many of the metallic salts, as those of iron, zinc, copper, and lead; and some of the earths, when combined with acids, of which alum is a striking example. The vegetable kingdom, however,
Narcotics, at the head of which stands opium, will frequently assume the character of astringents, by diminishing the irritability upon which increased discharges depend. In Diarrhoea, an astringent, properly so called, diminishes the flow of those acrid fluids into the intestines, by which their peristaltic motions are prÆternaturally increased, and it consequently represses the diarrhoea; a narcotic, under similar circumstances, might not repress the flow of the acrid matter to which I have alluded, but it would render the bowels less susceptible to its stimulus, and would therefore produce the same apparent alleviation, although by a very different mode of operation. There is yet a third species of remedy, which
Astringents are capable of being exclusively used as local applications, and when they are so employed for the purpose of stopping hemorrhage, they are termed Styptics.
LOCAL STIMULANTS.
This Second Division comprehends those medicinal substances, which have been generally classed under the head of Evacuants; for, as they stimulate particular organs, so do they occasion by their local operation, an increased secretion, or evacuation from them.
EMETICS.
Substances which excite vomiting, independent of any effect arising from the stimulus of quantity, or of that occasioned by any nauseous taste or flavour.
Before we can determine the modus operandi of emetics, it will be necessary to take an accurate view of the phenomena and pathology of vomiting.
Although we shall not be disposed to receive this theory in its full extent, yet we cannot hesitate to admit that the influence of the nervous system is indispensably necessary for producing vomiting; and we accordingly find that this act will not take place, however forcibly the stomach may be goaded by emetics, where the energy of the nervous system is suspended, as in cases of profound intoxication, or in violent wounds and contusions of the head; while if the brain be only partially influenced, as by incipient intoxication, or by a less violent blow upon the head, its irritability is increased instead of being paralysed, and vomiting under such circumstances is excited by the slightest causes: the fact of such opposite results being produced by the same impulse in different degrees of intensity, is no less curious than instructive. Dr. Richard Harrison, in his Gulstonian Lecture before the College of Physicians, treated the subject of vomiting with much ingenuity, and I am disposed to adopt the views which he offered. He observed, that although the experiments of Majendie sufficiently testify the importance of the pressure of the abdominal muscles upon the stomach in the act of vomiting, and which can only be explained by the influence of the brain and nervous system, yet that he has attributed too much to their agency; “it appears to me,” continued he, “that vomiting may be explained in the following manner:—the irritation of the stomach makes a call upon the brain for the aid of the diaphragm and the abdominal muscles, in order to expel its contents; the diaphragm then becomes contracted and fixed, the ribs drawn down, and the abdominal muscles drawn inwards, so that the stomach is pressed on all sides by voluntary muscles, which, together WITH ITS OWN CONTRACTION, expel the contents.” Now it must be obvious that where the brain, from oppression or injury, is unable to transmit its influence to these muscles,
Vomiting may also be produced by the primary operation of certain agents upon the brain, by which its energy is disturbed, as by narcotics, or by the motions of swinging, whirling, and sailing: in such cases, the series of actions necessary for the establishing of vomiting, commences in the brain, and is propagated by nervous sympathy to the stomach.
When an emetic is taken into the stomach, an interval of twenty minutes or longer, usually passes without any apparent effect; an uneasy sensation, which we term nausea, is then felt, and this continues to increase until vomiting begins; here then we perceive are two distinct stages, each of which is marked by its own proper symptoms; the relative intensity and duration of which will be found to vary according to the nature of the exciting causes; thus some Emetics, as Sulphate of Zinc, act without occasioning much nausea, while others, as Tobacco excite it to a degree which is far greater than is proportioned to their emetic power: this is a fact of great importance in directing us in the selection of an Emetic, for we shall find that in some diseases it is a great object to avoid that state of system which invariably accompanies nausea, while in others it affords the best mode of answering an important indication of cure.
Nausea would seem to depend upon the exertions of the stomach and muscles, not being proportioned to the effects of the brain, in order to produce vomiting. Where this balance however is maintained, as during the operation of an ordinary emetic, the following are the symptoms which characterise the two stages;—while the nausea only is present, the countenance is pale and shrunken, the pulse feeble, quick, and irregular, and there is a feeling of cold; but as soon as vomiting commences, the face becomes flushed, the pulse quicker and stronger, although it seldom returns to its natural standard, until some time after the vomiting has ceased.
The feeble state of the circulation, as indicated by the pulse, and the general coldness and languor experienced during a paroxysm of nausea, are to be ascribed to those sympathetic relations by which the brain, stomach, and heart, are reciprocally influenced.
The advantages to be obtained from the administration of an emetic in the cure of disease, may either depend upon its primary, or secondary operations, that is to say, upon the mere evacuation of the stomach, or upon those changes which occur in distant parts from sympathy; and the judicious practitioner, in the selection of an emetic, will always be guided by the nature of the indication which he intends to fulfil; if his object be to evacuate the stomach quickly and completely, he will avoid those emetics that are distinguished by their nauseating tendency, as in cases of disease which depend on a disordered state of stomach, connected with undue distention, and the presence of acrid and indigestible matter; if, on the other hand, his intention be to influence some remote organ through the sympathetic powers of the stomach, an emetic of an opposite tendency may be better calculated to answer such indications: in some cases, he is to seek a beneficial result from the mechanical action of the diaphragm and abdominal muscles, by whose pressure the gall-bladder and hepatic ducts are emptied of their contents, and hence jaundice, arising from the obstruction of biliary calculi, has been suddenly removed by the concussion of an emetic: a similar pressure upon the thoracic viscera may occasion expectoration, and relieve the bronchial vessels in cases of asthma, catarrh, and croup.
Vomiting, when produced by the operation of a mild emetic, does not appear to exhaust the excitability of the stomach, but on the contrary to increase its tone; for we generally find the process of digestion is carried on more vigorously afterwards; although it is probable that, by frequent repetition, a different result would be obtained, and we should find that its motion would become liable to inversion by slight stimuli: we may therefore question the propriety of that practice which is so strenuously recommended by Hippocrates,
The benefits arising from the secondary effects of an emetic are numerous and extensive. It has been observed that during nausea the force of the circulation is considerably abated, hence the use of these remedies in hemorrhage; and, as the energy of absorption is generally in an inverse ratio to that of the circulation,
From the violent muscular exertions which take place in the act of vomiting, the administration of an emetic may be very injurious in certain
By violent and protracted retching, a person will sometimes become jaundiced; the stomach, diaphragm, and abdominal muscles, are, under such repeated efforts, apt to be rendered, to an eminent degree, irritable; so that at each effort of the former to discharge its contents, the latter will frequently be thrown into strong spasmodic contractions, and the liver together with the gall bladder will be suddenly caught, and, as it were, squeezed in a powerful press; in consequence of which the bile will regurgitate, and be carried into the VenÆ cavÆ; for Haller has shewn with what facility a subtle injection, when thrown into the hepatic duct, will escape by the hepatic veins; and upon which Dr. Saunders observes, “I know this to be a fact, for I have ascertained by experiment, that water injected in the same direction, will return by the veins in a full stream, though very little force be used.” When a jaundice is thus produced it will gradually disappear without the aid of any medicine; the kidneys are the principal means by which all unnecessary bodies are extracted from the circulating mass, a portion of bile will therefore under such circumstances be eliminated in every discharge of urine.
The different emetics employed in practice are derived from the vegetable and mineral kingdoms, some of which appear to produce their effects by an immediate impression upon the nerves of the stomach, while others require to be absorbed into the circulation before they display their energies. Ipecacuanha would seem to act primarily on the stomach, but Tartarized Antimony has been found, by experiment, to occasion vomiting, when injected into the veins of an animal; while the other mineral emetics, viz. the preparations of Copper and Zinc, undoubtedly operate on the stomach, and without inducing much nausea.
CATHARTICS:
Medicines which quicken or increase the evacuation from the intestines, or which, when given in a certain dose, occasion purging.
These remedies, from a general difference in their modes of operation, have been classed under two divisions—Laxatives and Purgatives. The former operate so mildly that they merely evacuate the contents of the intestines, without occasioning any general excitement in the body, or even stimulating the exhalant vessels of the canal; the latter produce a considerable influx of fluids from these vessels, and extend their stimulant effect to the system in general; and where these effects are very violent, the purgative is further distinguished by the epithet Drastic. Laxatives then may be said to empty the bowels simply, and to carry off extraneous
- 1. By stimulating the muscular fibres of the Intestines, whence their peristaltic motion is augmented, and the contents of the bowels more quickly and completely discharged.
- 2. By stimulating the exhalent vessels, terminating in the inner coat of the intestines, and the mouths of the excretory ducts of the mucous glands; by which an increased flow of serous fluids takes place from the former, and a more copious discharge of mucus from the latter; the effect of which is to render the fÆcal matter thinner and more abundant.
- 3. By stimulating the neighbouring viscera, as the Liver and Pancreas, so as to produce a more copious flow of their secretions into the intestines.
It appears that different purgatives have very different powers in relation to the several modes of operation above specified; some medicines, for example, urge the bowels to evacuate their contents by an imperceptible action upon the muscular fibres, and little or no increase of serous discharge attends the evacuation, such are Manna, Sulphur, and Magnesia; there would seem, moreover, to be certain bodies that have the property of increasing the peristaltic motions by operating as mechanical stimulants upon the fibre; it would not be difficult to derive many illustrations of this fact, from the history of herbivorous quadrupeds, and I have been disposed to consider the harsh and coarse texture which certain grasses assume in moist situations, as a wise provision in Nature to furnish an increased stimulus to the intestines of the animals who feed upon them, at a time when their diminished nutritive qualities must render such a result desirable; but the operation of a mechanical laxative may be demonstrated by a more familiar example; the addition of bran to our bread, constituting what is known by the name of Brown bread, induces laxative effects, merely from the mechanical friction of the rough particles, or scales of the bran, upon the inner coats of the intestines, for the wheat without the bran in bread is not particularly laxative.
Cathartics are essentially serviceable also in several diseases of the class Neuroses, which are generally intimately connected with a morbid condition of the alimentary passages; Chorea and Hysteria have been very successfully treated in this manner. The diseases incident to puberty in both sexes are also best relieved by a course of purgative medicines, and their effects in Chlorosis have conferred upon many of them the specific title of Emmenagogues.
But the therapeutical utility of Cathartics extends beyond the mere feculent evacuations which they may occasion. In consequence of the stimulating action which some of them exert upon the exhalent vessels, they abstract a considerable portion of fluid from the general current of the circulation, and are, on that account, beneficial as Anti-phlogistics. For the same reason they may act as powerful promoters of absorption, for there exists an established relation between the powers of exhalation and absorption, so that when the action of one is increased, that of the other is augmented.
Certain Purgatives, as I have just stated, exert their influence upon the neighbouring organs, and are calculated not only to remove alvine sordes, but to detach and eliminate foul congestions from the biliary ducts and pores.
With such facts before us, it is impossible to concede to the opinion of Dr. Hamilton,
The importance of cathartic medicines having been shewn, and the distinctions in their modes of operation established, it only remains to say a few words upon the subject of their abuse. All the remedies of this class, but more especially those of considerable power, require caution in their administration, even in those diseases where they are indicated by peculiar symptoms, especially if there be any tendency to inflammation, or to extreme debility, although this latter symptom is often rather apparent than real, and is at once removed by the brisk operation upon the bowels; during pregnancy and immediately after delivery, and during the flow of the menses, the prudent practitioner will use a discretionary caution in their exhibition. The too frequent use of these medicines will induce marasmus, and render the bowels so morbidly irritable, that purging is easily excited by the ordinary stimulus of our aliments; while in some habits the contrary obtains, and the resource to which the valetudinarian flies for relief only increases the torpor of the intestines, and confirms his costiveness.
The mode of adapting, combining, and administering Cathartics, will present subjects for our future consideration.
EMMENAGOGUES:
Medicines which are capable of producing the Menstrual discharge.
As Amenorrhoea, or retention of the menses, is generally the effect of a morbid state of the body, it follows that remedies capable of acting as Emmenagogues can only be relative agents, unless indeed we are disposed to accede to the opinion so generally maintained in the writings of the older physicians, but now generally discarded, that certain substances exert a specific
The suppression of the catamenia usually depends upon a debilitated state of the body, although it is sometimes the consequence of a plethoric diathesis; in the former cases tonics, in the latter, venesection may display the powers of an emmenagogue; upon which occasion, I have frequently derived the greatest benefit by cupping the patient upon the loins. Where the disease occurs in young women, about the age of puberty, it is very generally connected with extreme debility of the system; the preparations of iron, bark, and other invigorating medicines, are accordingly the most likely to succeed in its cure. Whereas in full florid habits, when the catamenia are suddenly suppressed, Laxatives, Diaphoretics, or blood-letting, afford the surest means of relief.
There are two other classes of medicine which may occasionally prove emmenagogue—Acrid Purgatives, which act upon the rectum, and hence by contiguous sympathy upon the uterus, as Aloes, &c. and Stimulating Diuretics, as Cantharides, the Turpentines, &c. which are supposed to excite the womb, sympathetically, by their stimulus upon the bladder. Nor is the advantageous influence of mercury to be overlooked, which, in cases of morbid action in the secreting functions, prove a Herculean remedy.
DIURETICS:
Medicines which increase the urinary discharge.
This effect is produced by very different modes of operation; and as some of them are mutually incompatible with each other, it is essential that we should understand the modus operandi of each individual of which the class consists, in order that we may direct its application with precision.
There is undoubtedly no tribe of medicinal agents more precarious in their nature and effects than that of Diuretics; this fact in a great measure depends upon the uncontrollable character of the organs upon which they act, but it must at the same time be admitted, that their failure frequently depends upon their modes of operation being directly incompatible with the state of the system at the time of their administration.
The following classification may perhaps serve to bring together the principal facts which are known upon the subject, and at the same time to display them in an order which is calculated to demonstrate their practical bearings and relations.
DIURETICS,
CL: I.—MEDICINES WHICH ACT PRIMARILY ON THE URINARY ORGANS.
1. By stimulating the secreting vessels of the kidneys, BY CONTACT.
a The medicines not undergoing any decomposition in transitu.
2. PotassÆ Nitras.
3. Oleum TerebinthinÆ.
4. Juniperus Communis.
5. Cantharides.
b The Medicines undergoing decomposition in transitu.
1. PotassÆ Acetas.
2. PotassÆ Super-tartras.
3. Scilla Maritima.
4. Colchicum Autumnale.
5. Copaifera Officinalis.
6. Spartii Cacumina.
CL: II.—MEDICINES WHICH ACT PRIMARILY ON THE ABSORBENTS, AND SECONDARILY ON THE KIDNEYS.
CL: III.—MEDICINES WHICH ACT PRIMARILY ON THE STOMACH AND PRIMÆ VIÆ, AND SECONDARILY ON THE ABSORBENTS.
1. By diminishing arterial action, and increasing that of Absorption.
1. Digitalis.
2. Nicotiana.
2. By increasing the tone of the Body in general, and that of the absorbent system in particular.
Bitter Tonics, &c. &c.
3. By producing Catharsis, and thereby increasing the action of the Exhalants directly, and that of the Absorbents indirectly.
1. Elaterium.
2. Jalap, &c. &c.
C. 1. Of Medicines which act Primarily on the Urinary Organs.
1. By stimulating the secreting vessels of the kidneys, by actual contact.
a The substance not undergoing any decomposition in transitu.
It is easy to imagine that any substance which is capable of entering the current of the circulation, and of stimulating the kidneys by a direct application to their secerning vessels, may occasion a more copious urinary discharge; in this manner the different saline
Water, as a simple diluent, will promote the action of the kidneys, and it is very judiciously remarked by Dr. Cullen, that by withholding the use of fluids in dropsy, you will diminish the quantity of fluids secreted, and allow the secretories of the kidneys to fall into a state of inactivity and collapse. This is a sufficient answer to those who defend the practice of enjoining an abstinence from all drinks in dropsy.
b. The diuretic remedy undergoing decomposition IN TRANSITU.
The digestive organs appear to possess the power of readily decomposing all saline compounds into which vegetable acids enter as ingredients, and of eliminating their alkaline base, which, being in the course of the circulation, carried to the kidneys, excites them into action, and promotes the excretion of urine; and it is probably in this way that the Acetate, Citrate, Super-tartrate, and other analogous combinations of Potass and Soda prove diuretic: on the other hand, it is equally evident that salts containing the mineral acids are not under the control of the decomposing powers of the chylo-poietic organs, and consequently do not undergo any changes in transitu, although some of these salts, as I have just stated, especially the more soluble ones, are absorbed entire, and prove diuretic. Sulphate of Potass, from its insolubility, is not readily absorbed, and its composition will not allow the developement of its base; we perceive therefore that it has not any tendency to produce an influence upon the urinary secretion.
Certain vegetable bodies likewise appear to occasion diuresis by a similar mode of operation, and it is worthy of notice that these medicines generally contain a bitter principle, which is probably separated by the analysing powers of the stomach; as exemplified in Scilla maritima; Colchicum autumnale; Lactuca Virosa; Gratiola officinalis; Spartium Scoparium (Summitates); Juniperus communis; Copaifera Officinalis (Balsamum,) &c. The stimulant powers of a bitter vegetable principle upon the primÆ viÆ, have already been fully noticed under the consideration of Tonics, (page 78), and it is reasonable to suppose, that an analogous principle, if introduced into the circulation, may exert a corresponding impulse upon the organs with which it comes into contact.
It particularly merits attention, that the diuretic operation of any body that acts by being absorbed, is at once suspended if catharsis follows its administration, whether in consequence of the largeness of its dose, its increased solubility, or from the effect of its combination with some purgative; for it is a law, that the processes of assimilation, and absorption from the duodenum, are arrested, or very imperfectly performed during any alvine excitement; the different effects of the saline compounds of the alkalies with tartaric acid, elucidate the truth of this law in a very striking manner—thus, Super-tartrate of Potass, or Cream of Tartar, in well regulated doses, acts, as we all know, upon the kidneys; the tartaric acid being, as I suppose in this case, abstracted and assimilated by the digestive process, and
Sulphate of Magnesia does not readily produce any diuresis, because it operates upon the bowels, but the experiments of Vitet and Bracy Clarke have shewn, that if this saline compound be administered to the horse whose bowels are not easily affected by purgatives, it acts powerfully upon the kidneys;
Equally necessary is it to attend to the state of the vessels of the skin, for if during the administration of a Diuretic, these vessels be excited by external warmth, its action may be diverted from the urinary organs to the exhalants on the surface, and occasion diaphoresis; but if the surface of the body be kept cool, this diversion will not occur: so greatly indeed does cooling the surface determine to the kidneys, that the usual diaphoretic medicines may, by an attention to this circumstance, be converted into powerful diuretics.
C. II. Medicines which act Primarily on the Absorbents, and Secondarily on the Kidneys.
It has been shewn, in the former division, that by increasing the action of the kidneys, we diminish the quantity of water in the blood, and consequently occasion an extraordinary action of the absorbents to supply the deficiency, whence dropsical accumulations disappear; it remains to be stated that an operation, which may be considered the converse of the one just described, is not unfrequently established: the absorbent vessels, in
C. III. Medicines which act Primarily on the Stomach or System, and Secondarily on the Urinary Organs.
A Diuretic effect is very frequently occasioned by substances which act on the stomach and primÆ viÆ, producing a peculiar state of these organs, which sympathetically affects the whole body, and more particularly the absorbent system, and the vessels concerned in the secretion of urine from the blood. As this primary influence upon the stomach, and the effects to which it gives rise in remote parts, are very different in their character, according to the nature of the remedy employed, and the state of the system at the time of its administration; the present attempt to investigate and generalize these relations, and to adopt them as the basis of a classification, may ultimately lead the practitioner to some distinctions of practical utility.
1. By diminishing Arterial Action, and increasing that of Absorption.
It would appear that the action of the vessels employed in the circulation of the blood, and the energy of the absorbents are, to a certain extent, antagonist powers; the experiments of Majendie demonstrate that the absorption of a poisonous substance is retarded by a plethoric, and accelerated by a depleted state of the sanguineous system; the fact is practically established by numerous phenomena in pathology. Dr. Blackall has very satisfactorily shewn the existence which subsists between increased arterial action and diminished absorption. Hence it follows that remedies capable of controlling the circulation may affect the activity of absorption, increase diuresis, and cure dropsy; in this manner the Digitalis Purpurea acts as a sorbefacient, and it may be remarked that it seldom or never produces its diuretic effects, without a concomitant reduction of the frequency of the pulse; its power too appears only when it is administered in dropsy; in a state of health it will reduce the pulse, but not increase the discharge of urine. Tobacco has also somewhat analogous powers in promoting absorption, and its operation is accompanied with a corresponding depression of vascular action. Venesection, upon the same principle, may occasion, in certain cases of dropsy, a discharge of the accumulated fluid.
That diminished absorption, and the consequent accumulation of serous fluids in the cellular texture, and different cavities, frequently depends upon general debility is very obvious, whence fevers, whether of the intermittent, or continued kind, which have been long protracted, are followed by oedematous swellings. In states of extreme debility the exhalant vessels would seem, from their laxity, to permit the thinner parts of the blood to pass too readily through them; this is proved by the circumstance that palsied limbs, in which such a laxity may be presumed to exist, are frequently affected with oedema, and the truth of this explanation is still farther corroborated by the advantages which accrue on these occasions from the mechanical support of pressure from bandages. In such cases, those remedies which are capable of renovating the vigour of the body can alone prove of any signal service. Dr. Blackall presents us with an illustrative case of this nature, on the authority of Mr. Johnson of Exeter, in which the tonic powers of well fermented bread occasioned in the space of a few hours an effect so powerfully diuretic, as to have cured sailors on board of the Asia East Indiaman, who had been attacked with Dropsy, in consequence of the use of damaged Rice.
Thus then do Diuretics, in some cases, cure by Evacuating, while in others, as in the instance above cited, they Evacuate by curing.
A case has lately occurred in my own practice, which not only affords a striking illustration of the present views, but is well calculated to convey to the inexperienced practitioner a very instructive lesson of caution. A man of the age of thirty-five, of the most dissolute habits, was attacked after a debauch of several days’ continuance, with inflammatory symptoms in the chest; a very large quantity of blood was suddenly abstracted, and the bleeding was repeated after the interval of a few hours. The respiration became laborious, and I was desired to visit the patient; I found that little or no urine had been evacuated since the attack, and that there were evident symptoms of effusion, the legs were swollen, and the difficulty of breathing was rapidly increasing. Under these circumstances I directed a large dose of Ammonia with some stimulating diuretics, which were to be repeated at short intervals. On the following day the distressing symptoms had subsided, a large quantity of urine had passed, and the patient expressed himself greatly relieved; unfortunately, however, in consequence of a slight increase of his distress in the evening, an injudicious friend in attendance, took more blood from the arm—the dropsical effusions rapidly increased, and life was extinguished in the course of three days by confirmed Hydrothorax.
3. By producing Catharsis, and thereby increasing the action of the Exhalants directly, and that of the absorbents indirectly.
It has been already stated, under the consideration of Cathartics, that certain medicines of that class excite the exhalants of the alimentary canal, and occasion a very copious discharge of serous matter: by this operation the blood is deprived of a large portion of water, and the absorbents are thus indirectly stimulated to supply the deficiency; Elaterium, and some other hydragogue cathartics, may be thus employed with extraordinary
The observations which I have thus offered will lead the practitioner to select the particular diuretic which is best calculated to fulfil the indications of each individual case; and they will at the same time point out those which cannot be administered in combination, without a violation of the law of medicinal compatibility. With respect to the general efficacy of these medicines it may be stated, that where the disease originates from organic affections of the chylo-poietic viscera, it will not be cured by the mere evacuation of the water by diuretics; but that where it has taken place from diminished absorption, these remedies may be reasonably expected to effect a cure.
DIAPHORETICS.
The term Diaphoretic has been applied to those medicines which increase the natural exhalation of the skin, and when they act so powerfully as to occasion sweating, they have been commonly distinguished by the name of Sudorifics, but as no difference exists between these remedies, but in the degree of force with which they act, we may very properly comprehend the whole under the general title of Diaphoretics: the fluid effused is also in both cases similar, but in the one it is discharged more slowly, and is carried off by the conducting
As obstructed perspiration may depend upon very different, and even opposite states of the system, so may the most adverse medicines fall under the denomination of diaphoretic remedies.
In some affections, a deficient diaphoresis may be associated with increased vascular action, and in others, with a slow languid circulation.
In conformity with the plan adopted on other occasions, I shall proceed to investigate the powers of this class of medicines, according to their supposed modes of operation.
DIAPHORETICS
Occasion their effects—
I. By Stimulating the Cutaneous Capillaries.
A. By external application.
The Stimulus of Heat, Frictions, &c.
B. By Medicines which enter the circulation and stimulate the cutaneous vessels by contact.
Mercurials—Sulphur.
C. By Medicines which act on the surface sympathetically, through the medium of the Stomach.
Cold Drinks, &c.
II. By Increasing the General Action of the Vascular System.
Violent Exercise—Ammonia—Guaiacum—Alcohol—Warm Bath.
III. By relaxing the morbidly constricted mouths of the Perspiratory Vessels.
Antimonials—Cold Affusion—Venesection—Saline Diaphoretics.
The action of the cutaneous vessels may be augmented by heat, without necessarily increasing, at the same time, that of the heart and arteries; hence it is that heat is, of itself, often sufficient to produce sweating, while it generally accelerates the operation of a sudorific medicine. To this general proposition, however, there are some very important exceptions; and, indeed, in certain conditions of the cutaneous surface, the stimulus of heat will be even found to impede, rather than to promote, diaphoresis; thus in the hot stage of a continued fever, there would seem to exist a peculiar constriction of the perspiratory vessels, accompanied with extreme heat and dryness. In such a state, remedies of the third class must be applied, or conjoined with those of the former. The warm bath may be said to partake of all the qualities upon which our classification is founded; it will stimulate the cutaneous capillaries,—increase vascular action, generally, and, by its emollient powers, relax the morbidly constricted mouths of the perspiratory vessels. During the ardent heat of fever, the external application of cold is the most efficient sudorific, as the valuable reports of Dr. Currie have very satisfactorily established.
Although the external application of cold was not often employed in the hot stage of fever, until within the last thirty years, yet the administration of cold drinks appears to have been practised by the ancients, as an expedient to produce perspiration. Galen, and his immediate disciples, as well as the physicians of the sixteenth century, seem to have frequently
Alcohol, Guaiacum, and other powerful stimulants, produce their effects by merely accelerating the circulation; but in employing such remedies for the purpose of exciting sweat, we must be careful to adapt them to the circumstances of the case, and to the degree of action which prevails. In all febrile diseases attended with much increased heat, or connected with local inflammation, diaphoretics of this description must be very cautiously administered, for by accelerating the circulation they might counteract any benefit which they would otherwise confer by relaxing the vessels of the skin. In the whole history of medical opinions there is scarcely a theory which has proved so fatal in its practical applications as that maintained by Van Helmont, and his disciples, viz. that acute diseases were to be cured by expelling some morbific matter, after its proper concoction—a theory which suggested the administration of the most stimulating sudorifics, together with high temperature
Saline Diaphoretics, as they readily pass with the chyle, may be supposed to enter the circulation, and be thus brought to act, directly, on the cutaneous vessels; at the same time it seems extremely probable that such remedies may also occasion an impression on the stomach, which is sympathetically communicated to the vessels of the skin; they have undoubtedly little or no influence on the general vascular system, and neither augment the force nor the velocity of the circulating current.
It is not, however, in febrile affections alone that this class of remedies proves highly beneficial; the very intimate sympathetic connection which subsists between the functions of the lungs and skins, renders the use of such medicines particularly advantageous in the cure of the diseases incident to the former of these organs; a fact upon which we shall hereafter offer some remarks under the history of Expectorants.
So again, in the treatment of bowel affections, in consequence of the
From the influence which these medicines exert upon the extreme vessels of the skin, they are also highly serviceable in various obstinate cutaneous affections, as Herpes, Lepra, &c.
As evacuating the serous part of the blood must necessarily have an indirect effect in promoting absorption, Sudorifics have been occasionally exhibited in Dropsy, especially in that form of the disease called Anasarca. It has been already observed that cases too frequently occur in which the discharge of urine cannot be increased by art; upon such occasions practitioners have sometimes had recourse to a trial of Sudorifics,
There is still another point of view in which the therapeutic importance of Diaphoretics may be considered. It is generally acknowledged that by cutaneous transpiration a portion of excrementitious matter is ejected from the system; hence by the failure or imperfect performance of this function, a deleterious fluid is retained which may give origin to disease; to such a cause may perhaps be attributed the generation of Calculi, and other diseases of the urinary system, as we shall have occasion to notice under the head of Lithonthryptics.
The increased efficacy which these medicines derive from combination with each other, will form a subject of interesting enquiry in the succeeding essay.
EXPECTORANTS.
Medicines which are supposed to be capable of facilitating the excretion of mucus from the breast, ex pectore, that is, from the trachea, and cells and passages of the lungs.
If the term Expectorant be intended to express a medicinal substance which has the power of promoting the expulsion of fluid from the lungs, by some specific action on the parts concerned, we can have no hesitation in at once rejecting the word, and denying the existence of such remedies: if, however the term be received, conventionally, as comprehending
A CLASSIFICATION OF EXPECTORANTS,
CL: I—MEDICINES WHICH INCREASE PULMONARY EXHALATION, AND THEREBY DILUTE THE MUCUS IN THE FOLLICLES OF THE LUNGS.
a. By removing constriction of the Pulmonary Exhalant vessels.
Blisters.
Venesection.
Nauseants.
b. By stimulating these vessels by the actual contact of a medicinal substance.
Allium.
Scilla?
The different Balsams.
foetid Gums.
c. By stimulating the top of the trachea, and thereby increasing the action of the exhalant vessels of the lungs, by a species of Contiguous Sympathy.
Stimulating Lozenges, Linctusses, The Inhalation of certain vapours, &c.
CL: II.—MEDICINES WHICH DIMINISH THE INORDINATE FLOW OF FLUID INTO THE LUNGS, AND RENDER THE EXPECTORATION OF THE REMAINDER MORE EASY.
a. By removing the debility of the Exhalants.
Sulphate of Zinc.
Bitter Tonics.
b. By increasing the power of the Absorbents.
Digitalis.
Nicotiana.
c. By determining to the skin by gentle diaphoresis.
Tartarized Antimony.
d. By exciting serous discharges from the bowels.
Saline Purgatives.
CL: III.—MEDICINES WHICH OPERATE, MECHANICALLY, IN PROMOTING THE REJECTION OF ACCUMULATED MUCUS.
a. By stimulating the muscles of Respiration.
Ammonia.
b. By exciting vomiting, and thereby compressing the thoracic viscera.
Emetics.
I. Of Medicines which increase Pulmonary Exhalation.
a. By removing constriction of the Pulmonary Exhalant vessels.
There can be no doubt but that, in certain states of disease, the exhalants of the lungs, like those of the skin, are affected by a spasmodic constriction, in consequence of which the usual quantity of fluid for the lubrication of these parts, is not effused, whence a train of morbid phenomena arise; this appears to happen in Pneumonia, Asthma, and certain other diseases of the pulmonary organs. In order to remove such a constriction, remedies of the Antispasmodic class may be exhibited with advantage; nauseating doses of Tartarized Antimony, or of Ipecacuanha, are likewise calculated to fulfil the same indication, by an operation analogous to that by which Diaphoresis is produced. If the term might be allowed we should call such remedies Pulmonary Diaphoretics. It is in this way that Venesection, Blisters, and other anti-phlogistic remedies, may in certain states of the lungs restore a healthy excretion from these vessels.
b. By stimulating the Pulmonary Exhalants, by the actual contact of a medicinal substance.
There certainly appear to be substances which enter the circulation, and are more peculiarly determined to the pulmonary vessels, since their odour is to be distinctly recognised in the air that is expired. Garlic may be adduced as an example of this kind; so penetrating is its odorous principle, that if it be only applied to the soles of the feet it may be perceived in the breath. Such substances may stimulate the exhalant vessels through which they pass, and by this stimulus the secretion may be increased, and the mucus contained in the follicles diluted, so as to be poured out in a less viscid form, and consequently in a state to be more easily brought up by expectoration.
c. By stimulating the top of the trachea, and thereby increasing the activity of the Exhalant vessels of the lungs, by a species of contiguous sympathy.
The salutary operation of those various remedies, which are allowed to pass slowly over the fauces, sufficiently establish the fact which is here announced. In this manner I apprehend that much benefit may arise from the use of a Linctus, and I am satisfied from experience that certain cases of hoarseness are to be frequently removed by such an application of stimulating syrups.
The inhalation of certain vapours will also enable us to make a more direct application to these parts; as, however, it is my intention to dedicate a chapter to the consideration of this form of remedy, it is unnecessary to dwell upon it in this place.
II. Of Medicines which diminish the inordinate flow of fluid into the lungs.
a. By removing the debility of the Exhalants.
It not unfrequently occurs in persons either debilitated by age or disease, that the exhalant vessels of the lungs lose their tone, and pour out a larger quantity of fluid than is necessary for the lubrication of these organs; this is particularly observable in the disease called humoral asthma, and in the catarrh of old persons: if this excess be restrained by strengthening the tone of the system generally, or by astringing these vessels in particular, the expectoration of the remainder will be rendered much more easy. According to my experience, sulphate of zinc displays considerable powers in moderating this effusion of fluid, and it appears to produce this effect by increasing the tone of the exhalant vessels of the lungs; several medicines also, which are included in the former division of this classification, may, by stimulating these organs, not only promote the exhalation when it is too scanty, but repress it when it is too abundant.
b. By increasing the power of the Absorbents.
In some cases, the mucous inundation may not depend upon any fault in the exhalants, but upon a torpid state of the pulmonary absorbents: our remedy for this evil is to be found amongst that class of medicines which have the power of promoting absorption, as small doses of some mercurial preparation, Digitalis, and perhaps Nicotiana, &c.
c. By determining to the skin by a gentle diaphoresis.
It is evident that an increase of the cutaneous exhalation is generally attended with a relative diminution in the other serous excretions of body; this is so obvious with respect to our urinary discharge, that every person must have noticed the variation of its quantity at different seasons of the year: in like manner the exhalation from the lungs, although less capable of becoming an object of observation, is not less affected by the state of the cutaneous discharge; hence medicines capable of promoting it, are calculated to diminish the quantity of serous exhalation from the lungs; and it is upon this principle, that well regulated doses of the compound powder of Ipecacuan], frequently furnish the oppressed asthmatic with a valuable resource.
d. By exciting serous discharges from the bowels.
Upon the principle announced in the preceding section, the operation of a saline cathartic may relieve the pulmonary organs when loaded with a preternatural accumulation of fluid, and consequently assist expectoration. On the contrary, if the exhalation be deficient, this class of remedies may increase pulmonary irritation, and check expectoration, a fact which coincides with the concurrent testimony of many able practitioners.
III. Of Medicines which operate mechanically.
a. By imparting vigour to the respiratory muscles, engaged in the act of expectorating.
It must be admitted that, to a certain extent, expectoration is a voluntary operation, connected with the action of a variety of muscles, which in a state of extreme debility are not easily excited into action: every practitioner must have noticed this fact during the treatment of the coughs of exhausted patients, and have witnessed the distress necessarily arising from it; in this condition, the exhibition of a stimulant may so far renew the exhausted excitability of these organs, as to enable them to undergo the necessary exertions.
b. By compressing the thoracic viscera, through the operation of an emetic.
The beneficial results which frequently attend the concussion of an emetic, in cases of mucous accumulations in the lungs, are too well known and understood to require much elucidation: in the act of vomiting the thoracic viscera are violently compressed, the neighbouring muscles are also called into strong action, and both expiration and inspiration are thus rendered more forcible, and the expulsion of mucus from the cavity of the lungs necessarily accomplished.
The safety and expediency of such a resource must, however, in each particular case be left to the discretion of the medical practitioner.
Besides the remedies above enumerated, there are some others which afford relief in certain coughs, and have therefore in popular medicine, been considered as Expectorants; but their operation, if they exert any, is to be explained upon principles altogether different from that of facilitating expectoration, and will more properly fall under the head of Demulcents.
Atmospheric changes, in relation to moisture and dryness, deserve some notice before we conclude the history of expectorant agents: the subject teems with curious and important facts, and the advantages which the asthmatic patient derives from such changes merit farther investigation. That the lungs are constantly giving off aqueous vapour is made evident by condensing the expired air on a cold surface of glass or metal; and it is easy to imagine that when the atmosphere is saturated with moisture, its power of conducting off this vapour will be proportionably diminished, and that an accumulation of fluid may thus take place in the lungs; on the other hand, we may suppose the air to be so dry as to have an increased capacity for moisture, and to carry off the expired vapour with preternatural avidity; in either of these cases, the excretions from the lungs will be materially influenced, whether to the benefit or disadvantage of the patient will depend, in each particular instance, upon the nature of the disease under which he suffers. I have known a person who could breathe with more freedom in the thick fogs of the metropolis than in the pure air of a mountainous region, and it would not be difficult to adduce many examples in illustration of a diametrically opposite constitution of the pulmonary organs.
From the same cause we may frequently observe remarkable changes
In the course of considerable experience in the treatment of pulmonary complaints, and in the influence of climate and seasons upon them, I have repeatedly observed the rapid transition from moisture to dryness to occasion very remarkable effects upon the disease; and I much question whether an attention to such a condition of the atmosphere does not deserve as much consideration in the election of a suitable place of residence for such invalids, as the more obvious circumstance of temperature. I have been long in the habit of recommending to persons confined in artificially warmed apartments, to evaporate a certain portion of water, whenever the external air has become excessively dry by the prevalence of the north-east winds, which so frequently infest this island during the months of Spring; and the most marked advantage has attended the practice. But in such cases the practitioner must ever be guided by the symptoms of each particular case; it would be worse than useless to lay down any general precept for his guidance. We cannot then be surprised that such a difference of opinion should exist amongst practitioners of equal eminence, respecting the influence of a marine atmosphere; some advocating its advantages to the pulmonary invalid, and others maintaining with equal confidence the injurious tendency of such localities; each party appeals to experience in justification of his opinion, and with equal candour and justice; but the cases from the results of which the medical inference has been drawn, however parallel they may have appeared, differed in those essential points to which we have alluded, and upon which the question of climate would seem to turn. There is another circumstance connected with the subject of atmospheric moisture which it is also essential to remember,—that the air gains a considerable increase in its power of conducting caloric, by becoming saturated with aqueous vapour; thus, when a thaw takes place, and the thermometer rises a few degrees above 32°, the air, instead of impressing us with the sensation of increased temperature, actually appears much colder.
SIALOGOGUES;
Substances which increase the salivary
1st. Those which increase the salivary excretion by external application to the secreting vessels, by mastication, as the following acrimonious and pungent substances, Anthemis Pyrethrum; Colchearia Armoracia; Daphne Mezereum; Nicotiana Tabacum, &c.
2nd. Those whose internal exhibition affects these organs through the medium of the circulation, of which Mercury is the only true example; for all the preparations of this metal, when administered in certain quantities, produce salivation.
The acrid Sialogogues, or Masticatories, by stimulating the excretory
Mercury, in its metallic state,
Sir Gilbert Blane
But do not the kidneys, and other excretory glands also furnish outlets, through which the detritus of the body is eliminated. How does it happen, therefore, that the kidneys are not as equally affected as the salivary glands by the action of mercury? In the present state of our knowledge it will be more prudent to rest on the phenomenon as an ultimate fact, than in attempting to ascend higher in the scale of causes, to involve ourselves in impenetrable darkness.
During the prevalence of the theory which attributed to Nitric acid all the antisyphilitic powers of mercury, it was even maintained that this acid also excited ptyalism; experience however has disproved the effects thus attributed to it, and no one attempts to support its pretensions, as a sialogogue, except indeed as it may perchance, by its acrid qualities, influence the excretory ducts of the glands, externally, in the act of being swallowed.
It has very lately been stated by Dr. Macleod,
Some theorists may, perhaps, be inclined to consider certain Nauseating Medicines as possessing sialogogue properties. It cannot be denied that an increased discharge of saliva will take place during the operation of such remedies, but it is very transient, and can never be rendered available to any therapeutic object. I shall however have occasion to refer to this fact hereafter, and to the inference deduced from it by Dr. Eberle, in explanation of the effect of nauseating medicines in promoting the operation of Mercury.
ERRHINES, or STERNUTATORIES:
Substances which, by direct application to the pituitary membrane, occasion a discharge from the nostrils either of a mucous or serous fluid. This class contains several different species, whose operation varies in intensity, as well as in duration.
Errhines have been regarded as useful in consequence of the evacuation they occasion, but in this respect their value has been greatly over-rated; it has been stated, that they diminish the quantity of fluid circulating
Dr. Cullen has moreover supposed, that these substances may be useful in preventing apoplexy or palsy. Morgagni
It has been a subject of popular inquiry, how far the habitual use of Snuff may prove beneficial or injurious; and whether the habit, when once fully established, can be discontinued with impunity? It may be remarked that Snuff, by habitual use, soon ceases to produce the effect of an Errhine, for which reason its discontinuance cannot, generally, be regarded as likely to be attended with any danger; in those cases, however, in which the discharge is perpetuated, a contrary judgment should be pronounced, for all artificial discharges become constitutional by long continuance, and can therefore be seldom checked with impunity. Dr. Cullen states, from experience, that “whenever the nasal discharge has been considerable, the laying aside the custom of taking snuff has been productive of evil.”
EPISPASTICS. Vesicatories. Blisters.
External applications to the skin, which produce a serous or puriform discharge, by previously exciting a high state of inflammation.
When these agents act so mildly as merely to excite inflammation, without occasioning the effusion of serum, they are denominated Rubefacients.
Various substances have at different times, been proposed for the accomplishment of this object,—such as Nitric Acid, Boiling Water, Strong Acetic Acid, Tartarized Antimony, &c. It is, however, generally admitted, that no substance ever employed equals in efficacy, or certainty, the Cantharis Vesicatoria, the common blistering, or Spanish fly; and whose effects may serve to illustrate the modus operandi of this class of remedies.
From this simple view of the subject it will appear evident, that blisters may produce their salutary effects by several different modes of operation; by a just estimate of which the practitioner will be enabled to reconcile the discordant opinions which have been delivered upon the subject, and to employ these agents with greater satisfaction and advantage.
Blisters may act—
1. As Derivatives, i. e. by producing a derivation of the circulation from the inflamed and engorged vessels of the neighbouring organs to the blistered surface. This mode of operation was long overlooked by the physicians, who ascribed all the beneficial effects of a blister to the evacuation which it produced, while the humoral pathologist, moreover, considered the matter so discharged to be of a morbific nature. That such agents owe their salutary tendency to causes independent of their powers as evacuants, is at once rendered evident by the relief which they afford, when used only as Rubefacients.
2. As Evacuants—by occasioning an effusion of Fluids. In this case the vesicated part may be considered in the light of a new excretory organ, the formation of which requires the establishment of a new current or determination of blood; so long as the discharge continues, so long will there be an especial demand of blood in the blistered part, and a consequent derivation of the circulation from the inflamed and engorged vessels of the neighbouring organs.
3. As General Stimulants, by raising the vigour of the circulation.
4. As Antispasmodics.—Relieving pain through the medium of Contiguous Sympathy. This effect would frequently appear to be independent of the operations above enumerated; a similar principle seems to exist
It remains for us to make a few observations upon the abuse of these remedies, for, notwithstanding the popular adage that “Blisters are always safe things,” that “if they do no good, they can do no harm,” they will be found, like all other potent applications, capable of producing much mischief when directed by unskilful hands. In stages of high vascular excitement in the pulmonary organs, blisters have increased the irritation they were designed to allay, and in some cases have promoted a tendency to effusion; in the treatment of acute Hydrocephalus the common practice of blistering the head appears very questionable, and has too often, I am well persuaded, accelerated the fatal termination, by increasing the disposition to serous effusion.
ISSUES (Fonticuli) and Setons (Setacea
The effects of these processes bear a strong analogy to those which are produced by Vesicatories; they are, however, more permanent, and are on that account better adapted to the relief of those chronic affections which would seem to require a remedy of long continued influence. In pulmonary affections, for instance, a seton in the side is frequently attended with very considerable benefit. The popular belief in humoral pathology, which continues to influence the mass of mankind, has perhaps assigned to these remedies a greater share of credit than that to which they are really entitled, but it must still be acknowledged that when an ulcer having existed a great length of time, is healed or dried up, or any constitutional discharge is suddenly checked, the health may become affected. In such cases the establishing a discharge by means of an Issue is undoubtedly a safe, and often a beneficial operation.
III. OF CHEMICAL REMEDIES.
There is no principle in physiology better established than that which considers vitality as a power engaged in continual conflict with the physical, chemical, and mechanical laws, to which every species of inanimate matter is invariably subject. Every phenomenon of the living body might be advanced in illustration and support of this general position. The animal machine is constantly surrounded and assailed by agents, whose elective attractions for the principles of which it consists, are so numerous and energetic, that its decomposition would inevitably and speedily result, were not the adhesion of its molecules maintained by the conservative influence of a superior power. The compositions and decompositions which manifest themselves in the elaborate operations of chylification,
Substances which directly diminish the force of the circulation, and reduce the heat of the body, without occasioning any diminution of sensibility or nervous energy.
These remedies may be considered either as external and local, or as internal and general. In the first case, there will not be much difficulty in substantiating their claims to be considered Chemical Agents, but in the latter case, the theory of their operation is unsatisfactory and obscure; and even the facts which are adduced to establish the existence of such a class of remedies, are of a very problematical character.
Topical Refrigerants. In the case of external inflammation, refrigeration may be produced by the application of cold substances, such as water, ice, or certain saline solutions, or by the abstraction of heat by means of evaporation, which is very effectually accomplished by the use of lotions composed of spirit or ether. By these methods we are capable of directly diminishing the activity of the vessels of the part; thus, in burns and scalds, the pain is instantly relieved, and the inflammation effectually reduced.
Internal Refrigerants. There are certain saline substances which, by undergoing a rapid solution, and acquiring an increased capacity for caloric, produce a diminution of temperature, and if this takes place in the stomach, the sensation of cold which it will produce is equivalent to a partial abstraction of stimulus; which, being extended by sympathy to the heart, occasions a transient reduction in the force of the circulation, and by this, or by a similar sympathetic affection, causes a sensation of cold over the whole body; in this manner Dr. Murray explains the refrigerant operation of nitre, which after all is of a very doubtful nature. We shall perhaps not feel much difficulty in accepting this theory, and in allowing that general refrigerant effects may be temporarily produced, by occasioning an impression of cold upon the stomach. The theory which is proposed to explain the refrigerant operation of vegetable acids and certain other substances, and which we have now to consider, is derived from those chemical views respecting animal heat, in which the consumption of oxygen in the act of respiration is considered the principal source. Dr. Murray,
But it is known, that the animal temperature is derived from the consumption of oxygen gas by respiration; and, that an increase in that consumption will occasion a greater evolution of caloric in the system, and consequently an increase of temperature in the body, while a diminution in the consumption of oxygen will have an opposite effect. If, then, when the temperature of the body is morbidly increased, we introduce into the stomach substances containing a large proportion of oxygen, especially in a loose state of combination, we may succeed in reducing the general temperature. This we accomplish in part by a vegetable diet, but still more effectually by the free use of the Acids. The vegetable acids in particular, which are found by experience to be the best refrigerants, are readily acted upon by the digestive powers, and assimilated with the food; and as the large quantity of oxygen which they contain is already in a concrete state, little sensible heat can be produced by the combination of that element with the other principles of the food. The nutritious matter which is received into the blood, containing thus a larger proportion of oxygen than usual, will be disposed to abstract less of it from the air in the lungs, and consequently less caloric will be evolved; the temperature of the body will be reduced; and this, again operating as a reduction of stimulus, will lessen the number and force of the contractions of the heart.
Such is the philosophical web which chemical ingenuity has wove for us,—the device is beautiful, but the fabric will be found too frail to endure the touch. The experiments of Dr. Crawford, in proof of the chemical origin of animal heat, are highly ingenious and plausible, but it is now generally admitted that the temperature of animals depends upon the living principle
ANTACIDS:
Remedies which obviate acidity in the stomach, by combining with the acid, and neutralizing it.
This is the most decided instance of chemical action which occurs in the history of medicinal operations. We have an acid whose presence excites morbid symptoms in the primÆ viÆ, and these are immediately removed by the administration of any one of those substances which are capable of forming a natural compound with the acid in question, out of the body, and the same proportions are required in both cases for saturation.
ANTILITHICS and LITHONTHRYPTICS.
Antilithics
Lithonthryptics
It has been already shewn, while treating the subject of Diuretics, that certain substances, when internally administered, are capable of passing the barriers of digestion, and of entering the circulation; and that, moreover, these bodies may be again separated by the secretory vessels of the kidneys, and be ejected from the body in the urine. It cannot therefore be contended, that the urinary calculus is placed beyond the sphere of direct medicinal influence, nor can any argument, founded upon the alleged incompatibility of chemical and vital action, be fairly maintained in this case; for the urinary calculus, as well as the urine itself,
The urine may be considered as one of the most heterogeneous of the animal fluids;
| Animal Principles. | Water | 933·00 |
| Urea | 30·10 | |
| Lithic Acid | 1·00 | |
| Pure Lactic Acid, Lactate of Ammonia, and Animal matters not separable from these | 17·14 | |
| Mucus of the Bladder | ·32 | |
| Alkaline and Earthy Salts. | Sulphate of Potass | 3·71 |
| Sulphate of Soda | 3·16 | |
| Phosphate of Soda | 2·94 | |
| Phosphate of Ammonia | 1·65 | |
| Muriate of Soda | 4·45 | |
| Muriate of Ammonia | 1·50 | |
| Earthy Phosphates with a trace of Fluate of Lime | 1·00 | |
| Silex | ·03 | |
| | ||
| 1000·00 | ||
| | ||
Besides the above ingredients, which appear to be essential to healthy urine, Dr. Prout observes that in different diseases it may contain Albumen, Fibrin, and the red particles of the blood; Nitric acid; various acids, which are found to be modifications of the Lithic; Oxalic acid; Benzoic acid; Carbonic acid;
It will be necessary in this place to make a few observations upon the nature and habitudes of those principles, which are more immediately active in the production of calculi—
1. Urea is a principle peculiar to urine, and must be regarded as a result of the action of the kidneys upon some of the constituents of the blood, perhaps, as Dr. Prout suggests, upon its albuminous matter. For a long time it was regarded as the peculiar principle upon which the colour and other sensible qualities of the urine depended; Berzelius however has corrected this fallacy, and considers that the Lactic acid, and its accompanying animal matters, are the bodies which impart to this fluid the characteristic smell and colour which distinguish it.
Erythric Acid. When nitric acid diluted with about an equal bulk of water, is poured upon pure lithic acid, and a moderate heat is applied, an effervescence takes place, and the lithic acid is dissolved; if we then concentrate this solution by a gentle evaporation, we obtain transparent colourless crystals, which have been found to constitute a peculiar acid, to which M. Brugnatelli has given the name of Erythric acid.
Purpuric Acid. Dr. Prout has discovered that if into a strong solution of the above crystals in water, whilst boiling hot, we carefully drop some pure ammonia, the solution acquires a beautiful purple
3. The Phosphates. As the Phosphoric acid and its compounds perform an important part in the generation of calculi, their origin
Having thus briefly noticed those particular points in the chemistry of the subject with which the therapeutic principles are more immediately connected, we shall be better prepared to examine and appreciate the several plans of treatment which have been proposed for the prevention, cure, or palliation of calculous disorders; and here the subject naturally divides itself into two parts; the one comprehending the modus operandi of Antilithics, or those remedies which prevent or correct the calculous diathesis; the other, explaining the solvent action of Lithonthryptics over concretions already formed.
The line of demarcation by which healthy and morbid urine are separated, is so slight that it is difficult to define its limits; nor would the circumstance appear to be materially important, for the boundary is daily exceeded, not only with impunity, but even without our consciousness of the event; and Dr. Prout has accordingly denominated such occasional deviations, the “Sediments of Health.”
The same enlightened author considers that mechanical deposites from
Scheele,
| A TABULAR VIEW OF THE DIFFERENT SPECIES OF URINARY CALCULI. | |||
|---|---|---|---|
| Species of Calculi. | EXTERNAL CHARACTERS. | CHEMICAL COMPOSITION. | REMARKS. |
| 1. Lithic or Uric. | Form, a flattened oval; Specific gravity, generally exceeds 1·500; Colour, brownish or fawn-like; surface smooth, texture laminated. | It consists principally of Lithic Acid; when treated with nitric acid, a beautiful pink substance results. This calculus is slightly soluble in water, abundantly in the pure alkalies. | It is the prevailing species; but the surface sometimes occurs finely tuberculated. It frequently constitutes the Nuclei of the other species. |
| 2. Mulberry. | Colour, dark-brown; texture, harder than that of the other species; Sp. grav. from 1·428 to 1·976. Surface, studded with tubercles. | It is Oxalate of Lime, and is decomposed in the flame of a spirit lamp, swelling out into a white efflorescence, which is Quick-lime. | This species includes some varieties which are remarkably smooth and pale coloured, resembling a hemp seed. |
| 3. Bone Earth. | Colour, pale brown or gray; surface smooth and polished; structure, regularly laminated; the laminÆ easily separating into concrete crusts. | Principally Phosphate of Lime. It is soluble in muriatic acid. | |
| 4. Triple. | Colour, generally brilliant white; surface uneven, studded with shining crystals; less compact than the preceding species; between its laminÆ, small cells occur, filled with sparkling particles. | It is an Ammoniaco-magnesian phosphate, generally mixed with phosphate of lime; pure alkalies decompose it, extricating its ammonia. | This species attains a larger size than any of the others. |
| 5. Fusible. | Colour, greyish-white. | A compound of the two foregoing species. | It is very fusible, melting into a vitreous globule. |
| 6. Cystic. | Very like the Triple Calculus, but it is unstratified and more compact, and homogeneous. | It consists of Cystic Oxide; under the blow-pipe it yields a peculiarly fetid odour. It is soluble in acids, and in alkalies even if they are fully saturated with carbonic acid. | It is a rare species. |
| 7. Alternating. | Its section exhibits different concentric laminÆ. | Compound of several species, alternating with each other. | |
| 8. Compound. | No characteristic form. | The ingredients are separable only by chemical analysis. | |
It will appear evident from these cursory observations, that some varieties of Calculi will be influenced by acids, and others by alkalies, and that the exhibition of such remedies will be liable to palliate, or to aggravate the symptoms, according to the character and composition of the offending calculus, and according to the prevailing diathesis of the patient; as a general rule to direct us in the chemico-medical treatment of these cases, Dr. Marcet states, that “Whenever the lithic acid predominates, the alkalies
Independent of any chemical effect, alkaline substances are found by daily experience to allay the morbid irritability of the urinary organs in a manner not yet explained; alkalies may also prove generally serviceable in these disorders, by acting immediately upon the digestive organs, for the disposition of forming calculi is always, more or less, accompanied with the indications of deranged digestion; and it is probable that the first link of the series of actions, which cause this disposition, has its origin in the stomach.
The alkaline carbonates are found to answer as effectually as the pure alkalies, and they have the advantage of being less liable to disagree with the stomach. Mr. Hatchett has proposed the carbonate of magnesia, in doses of ?j to ?j, as a valuable substitute for alkaline remedies in cases of lithic calculi; but as its insolubility must render its absorption equivocal, the beneficial operation of the substance must principally depend upon its neutralizing any excess of acid in the primÆ viÆ, and in this way there can be no doubt of its lithonthryptic agency; “but,” says Dr. Marcet, “such is the tendency which the public has to over-rate the utility of a new practice, or to take a mistaken view of its proper application, that there is every reason to believe that the use of magnesia has of late years become a frequent source of evil in calculous complaints.” Lime-water has been also recommended for the purpose of fulfilling the same indications, and as not being liable to produce that irritability of stomach which frequently attends the long continued use of the fixed alkalies; besides which, some chemists have maintained that it exerts a peculiar solvent power over the cementing animal matter of the concretion, and thereby destroys its cohesion.
Where an acid is indicated, the Muriatic will in my judgment be found as convenient and effectual as any that can be administered. Mr. Brande proposes Cream of Tartar for this purpose; upon this point I differ with him, for this salt, to say the least of it, is questionable in its mode of operation; for although its first impression upon the stomach is that of an acid, the subsequent processes of digestion decompose it, and eliminate its base, which being absorbed acts upon the urinary organs as an alkali. I have seen a white sabulous deposit, consisting of the Phosphates, in the urine of persons after the constant use of Imperial as a beverage, which I am at a loss to explain upon any other principle. Sir Gilbert Blane has also very satisfactorily shewn, that a fixed alkali produces the same effect upon the urinary organs whether it be exhibited alone, or in combination with citric acid; in this latter case the salt undoubtedly undergoes a decomposition in transitu, as I have more fully explained under the consideration of Diuretics, (page 94.) During an alterative course of Lithonthryptic remedies it may be beneficial to interpose occasionally a purgative medicine, but we must not combine it with the lithonthryptic, at least, if we wish this latter medicine to reach the urinary passages; for it is a law which I have already attempted to establish (see page 94), that Catharsis suspends the process of alimentary absorption.
In order to ascertain how far this decomposition could be effected in the living body, the ingenious experimentalists selected a dog of rather large size, into whose bladder they introduced a fusible calculus attached to a sound, and between two conductors of platinum; the bladder was next distended by injecting tepid water, and the apparatus subjected to galvanic influence. After a little struggling, the animal became calm, and was subjected to the operation during an hour. On removing the sound, the calculus shewed unequivocal marks of decomposition. The same process was repeated, night and morning, during six days, when the friability of
ANTIDOTES.
Medicines which are capable of preventing the ill effects of a poison; or, of counteracting its fatal virulence.
There is perhaps no subject upon which the credulity of mankind has been so extravagantly exercised as on that of Poisons; nor is there, certainly, any class of remedies whose history has suffered so many vicissitudes from the caprice of hypothesis, as that of Antidotes.
It is not my intention, on the present occasion,
The abandonment of such notions may be considered as one among the many advantages which have arisen to medicine, from the cultivation of physiology.
Without farther introduction, I shall proceed to the main object of this work, and inquire how far a chemical agent may be capable of neutralizing, or of decomposing, a poisonous substance in the human body; and endeavour to ascertain the degree of confidence to which it may in each particular case be entitled; equally important is it to learn, whether certain vital agents may not be serviceable in cases of poisoning, either by promoting the elimination of the poison, or by producing a state of the system best calculated to resist its deleterious operation.
It may be safely asserted that we possess very few true antidotes; for although several of the mineral poisons may be neutralized or decomposed by various reagents, yet their destructive action is generally so rapid, that the mischief is effected before any chemical changes can avail; and, in other cases, the substances resulting from the chemical action, are as poisonous as the original ingredients, as in the case of the decomposition of Corrosive Sublimate, by the alkalies and earths, when the precipitated oxide is as virulent as the original salt; while, under certain circumstances, I suspect that the vital powers of the stomach are in direct opposition to those changes and decompositions which so readily, and so uniformly, take place in our laboratories. To vital agents then, the practitioner must principally look for succour; but before we can establish any general rules for the treatment of poisoning, it is essential to distinguish between the different modes in which poisonous substances produce their effects, or at least to determine the parts of the living system through which they act; for it will be found, that each poison has its own modus operandi, from which alone can be derived the particular indications of cure.
The hypotheses devised by the ancient physicians, to account for the destructive powers of these substances, were principally derived from mechanical notions respecting the supposed form of their particles, which they imagined capable of lacerating and disuniting the animal fibres by the sharpness of their spiculÆ;
Each of the three kingdoms of Nature furnishes a number of poisons, the investigation of whose chemical properties and physiological actions, and that of the symptoms to which their administration gives rise, the lesions of structure which they occasion, and of the medical treatment which they require, constitutes an elaborate branch of science designated by the term Toxicology, and of which I have more fully treated in my work on Medical Jurisprudence.
Poisons differ materially from each other, not only with respect to the modes in which they produce their effects in relation to the several vital organs, but with respect to their application; some of those, for instance, which, if introduced into a wound, are speedily fatal, may be taken into the stomach with complete impunity, as in the instance of the venom of the viper and other snakes, which appears to exert no influence on the stomach; others, on the contrary, display their deleterious action on the stomach alone, such as caustic acids, and alkalies, corrosive sublimate, and some chemical poisons; while others, again, are equally destructive whether applied to the inner surface of the stomach, or to the lower intestines, in the form of clyster, or even to the mucous membrane of the mouth or nose; to the eye; to the vagina and orifice of the uterus, or to an abraded portion of the skin. There is, moreover, a class of substances which may be termed Aerial poisons, for they may exist in the state of gas, or be held dissolved in the atmosphere, and be received by respiration, or by the mucous membranes of the nose and throat; the saliva may also thus become the medium for transferring various subtile poisons from the atmosphere to the animal body; this is well illustrated by the fact of the transfer of metallic influence, as related in the case of a gentleman in perfect health who became salivated in consequence of sitting for one hour by the side of a person who was in a state of mercurial ptyalism, in order to give him a lesson in botany.
It also deserves notice, that a poison acts with different degrees of force and celerity in different parts of the same tissue; its absorption, for instance, would appear to be energetic in proportion to the number of veins,
FoderÉ, in the fourth volume of his Medicine Legale, arranges poisons according to their action on the living system, and which, with a slight alteration in the order of the classes, has been adopted by Orfila, and most other writers on Toxicology. Poisons are thus reduced into six classes: viz. 1. Corrosive or Escharotic, as the Preparations of Mercury, Arsenic, Antimony, Copper, Tin, Zinc, Silver, Gold, and Bismuth; the concentrated Acids, and caustic Alkalies, and Earths; Cantharides; glass and enamel powder; diamond dust.
The value of this classification has been very justly stated to consist in its combining to a certain degree, the advantages of a pathological arrangement with those of one founded on the basis of Natural History; for, while it is strictly pathological, it at the same time distributes the different poisons, with some few and unimportant exceptions, in an order corresponding with that of their natural history. The First two classes, for instance, present us with substances of a mineral origin; the Third
These few objections, and many more might be urged, are sufficient to demonstrate the imperfection of the classification under consideration, and which must render it wholly unavailable to the physician in the treatment of cases of poisoning, who must derive his plan of cure from the physiological action of the substance against which he has to contend; thus, for instance, Arsenic and Corrosive Sublimate are both corrosive poisons, but so materially do they differ from each other in their physiological actions that, when swallowed, they will require for the preservation of the individual, a very different system of treatment.
For such reasons I have ventured to propose a new arrangement of Poisons, which may furnish the practitioner with a general theorem for the administration of Antidotes.
| A SYNOPTICAL TABLE OF POISONS, | |||
|---|---|---|---|
| NEWLY ARRANGED | |||
| According to the different Primary Operations, by which they produce their effects, | |||
| With a view to furnish a General Theorem for the administration of Antidotes. | |||
| CLASS I. | Poisons which act Primarily, through the medium of the Nerves, without being absorbed; or exciting Local Inflammation. | ||
| Order 1. | By which the functions of the Nervous System are suspended, or destroyed. | ||
| (Death by Suffocation from paralysis of the Respiratory muscles.) | |||
| Alcohol. | |||
| Aconite. | |||
| Oil of Tobacco. | |||
| Essential Oil of Almonds. | |||
| Camphor.[220] | |||
| Opium?[220] | |||
| Salts of Lead? | |||
| Croton Tiglium. | |||
| Order 2. | By which the heart is rendered insensible to the Stimulus of the Blood. | ||
| (Death by Syncope.) | |||
| Infusion of Tobacco. | |||
| Upas Antiar. | |||
| CLASS II. | Poisons which, by entering the Circulation, act through that medium, with different degrees of energy, on the Heart, Brain, and Alimentary Canal. | ||
| (Death in many forms.) | |||
| Arsenic. | |||
| Emetic Tartar. | |||
| Muriate of Baryta. | |||
| Hellebore. | |||
| Savine. | |||
| Meadow Saffron. | |||
| Squill. | |||
| Opium?[221] | |||
| Lettuce. | |||
| Henbane. | |||
| Prussic Acid. | |||
| Deadly Nightshade.[221] | |||
| Hemlock. | |||
| Camphor.[221] | |||
| Coculus Indicus. | |||
| CLASS III. | Poisons which, through the medium of the Circulation, expend their energies upon the Spinal Marrow, without directly involving the functions of the Brain. | ||
| (Death by Tetanic Convulsions.) | |||
| Nux Vomica—and the whole tribe of Strychnus. | |||
| CLASS IV. | Poisons which produce a direct local action on the Mucous Membrane of the Alimentary Canal. | ||
| (Death by Gangrene.) | |||
| Corrosive Sublimate.[220] | |||
| Verdigris. | |||
| Muriate and | |||
| Oxide of Tin. | |||
| Sulphate of Zinc. | |||
| Nitrate of Silver. | |||
| Concentrated Acids. | |||
| Caustic Alkalies. | |||
| Cantharides. | |||
| Bryony. | |||
| Elaterium. | |||
| Euphorbium. | |||
| Colocynth. | |||
| Hedge Hyssop. | |||
| Ranunculi. | |||
| Nitre. | |||
It was observed by BichÂt, and the observation has been fully confirmed by Brodie, that the influence of the brain is not directly necessary to the action of the heart; and is immediately necessary to life, only because the muscles of respiration owe their action to its influence.
Although the general proposition seems to be established, that the brain is not immediately necessary to the action of the heart, yet it must not lead us to the conclusion that the heart is therefore incapable of being affected by violent impressions on the nervous system; the fact is quite otherwise, for although the brain may be removed, and the circulation be nevertheless maintained by artificial respiration, yet an injury of another kind inflicted on the brain, may be followed by those immediately fatal consequences which decapitation itself would not produce; thus is a blow on the head commonly followed by syncope, and there are certain poisons that would seem to act in the same manner, such is the Infusion of Tobacco,
We come now to speak of the Second Class,—of those Poisons which enter the circulation, and act through that medium on the heart, brain, and alimentary canal. These organs, however, are affected in very different degrees by different poisons, or even by the same poisons, under different circumstances. Mr. Brodie has shewn that vegetable poison, although when introduced into the alimentary canal affect life, in consequence of the nervous sympathy which subsists between these surfaces and the common sensorium, yet, that the same poisons applied externally to a wound, produce their effects exclusively through the medium of the circulation, being conveyed to the brain only by mixing with the blood in its vessels, and not by being conveyed through the lymphatics, for a ligature upon the great blood-vessels prevents their producing deleterious effects; whereas a ligature upon the thoracic duct, or general canal through which all the absorbents pour their contents into the blood, does not in the least retard or prevent the operation of the poison. There are also several of the mineral poisons which, whether introduced into the stomach, or applied externally to a wound, poison the animal in consequence of being carried into the circulation. It had long been supposed that Arsenic occasioned death by inflaming the stomach; but Mr. Brodie has very satisfactorily shewn that its influence arises from its absorption, and that it must be regarded rather as a vital, than as a chemical agent. In the first place, he has found the inflammation of the stomach, in several cases, so
It has been just stated that after a poison has found its way into the circulation, it expends its virulence upon some particular organs. In some cases this is much more striking than in others. The preparations of Baryta, and of Tartarized Antimony, attack the heart, and occasion death by syncope. Arsenic is less definite in its action, it influences both the brain and the heart, but with different degrees of force in different cases, so that it is often difficult to ascertain which of these organs is the first to fail in its functions. Hydro-cyanic Acid is absorbed, and destroys life by its action upon the nervous system, whose energies it would seem to extinguish without any ostensible injury to the respiration and circulation; for in all those animals which were killed by it in the experiments of Orfila, Brodie, and others, the heart was found acting regularly, and circulating dark-coloured blood; and in some cases, this phenomenon was visible for many minutes after the animal was in other respects apparently dead.
Some substances would seem to direct their powers to various parts of the alimentary canal; and the appearance so produced might be mistaken for the effects of the local action of the poison, had they not been clearly proved by experiment to have arisen from an application addressed through the medium of the circulation; thus is inflammation of the primÆ viÆ induced by the contact of Arsenic with an external surface of the body!
The Third Class of my arrangement includes those poisons which enter the circulation, and, through that medium, expend their influence upon the spinal marrow, without directly involving the functions of the brain. M. Majendie, in the year 1809, submitted to the first class of the French Institute a series of experiments which had conducted him to the extraordinary result above stated. He found that an entire class of vegetables (the bitter Strychnus) possesses this singular property.
The Fourth Class comprehends all those substances which destroy life by a local action upon the alimentary canal, not by any impression upon their nerves, but by simply inducing a fatal lesion in the membranes.
Through one or more of the above modes of operation all poisons may be said to produce their fatal effects. In some cases a poisonous substance will be found to act in several different ways; thus, the Nightshade is evidently absorbed, carried into the circulation, and is enabled, through that medium to act upon the brain; at the same time it exerts a local action upon the stomach, although less violent than that occasioned by the acrid poisons; it moreover would appear, upon some occasions, to act directly through the medium of the nerves, like those substances
Having thus offered a summary of our present views respecting the physiological action of Poisons, we are prepared to lay down a general plan of treatment, which, it will be seen, can only be successful when conducted on principles strictly conformable with the just notions which the preceding experiments have so satisfactorily established.
Where a poisonous substance has, either through accident or design, found its way into the alimentary canal, three important indications are, if possible, to be fulfilled; and under these heads I shall offer such observations as may serve to instruct the practitioner in the philosophy of the general treatment, reserving the details to be observed in that of each poison, for more particular notice in a subsequent part of the work, where the history of these substances will be individually considered. The indications to which I allude are the following, viz.
1. The immediate ejectment of the poison from the body, by the operation of vomiting and purging.
Whatever may be the nature of the poison, we should endeavour with all possible expedition, to eject it from the body; and upon the promptness with which this is effected, the safety of the patient will generally depend; for the dangerous effects of such substances advance in a very increasing ratio, with the time they remain in contact with a living surface. A question may arise, whether in some cases it would not be judicious to attempt in the first instance the neutralization or decomposition of the poison; where a mineral acid, or a caustic alkali has been swallowed, it would undoubtedly be right to neutralize, and dilute it, as soon as possible, and then to excite vomiting, which may be advantageously effected by thrusting the finger down the throat, or by tickling the internal fauces with a feather: where an emetic is at hand, whatever may be its nature, it should be promptly given, but if circumstances will allow us the opportunity of selection, Antimony, Ipecacuanha, &c. should be rejected, and Sulphate of Zinc, or Sulphate of Copper, for several reasons, be preferred; in the first place they do not require much dilution
The practice of emptying the stomach by means of a syringe, as proposed by Boerhaave, has lately been revived with all the confidence of a new invention. There are cases of narcotic poisoning in which there can be no doubt it would furnish the practitioner with a valuable resource, but I much fear that it will be found to be less successful than its more sanguine advocates have anticipated; for where the stomach has so far lost its power as to be insensible to the stimulus of a potent emetic, the chances of recovery are small; the practice, however, in such cases ought never to be neglected, for it cannot possibly do harm, and may perhaps be beneficial.
After all has been ejected, which the operations of art can effect, we are to proceed, without delay, to the fulfilment of the second indication; viz.
2. The Decomposition of any remaining Portion, and the adoption of measures best calculated to obviate its absorption.
Where the substance is in a solid form, and acts by absorption, we should be very cautious how we favour its solution; while, if it exists in a liquid state, our object must be to render its active portion insoluble; this problem involves a series of questions which are wholly chemical. In order to prevent, or retard, the absorption of the active matter, we must, to a great degree, depend upon the agency of vital adjuvants; this latter indication however does not apply to Corrosive Sublimate and other substances which act upon the stomach locally, and are not absorbed; copious dilution also, in such cases, will frequently disarm the poison of its virulence,
Chardin, in his travels through Persia, informs us that when a Persian finds himself in a distressed situation, he has recourse to a piece of opium as large as the thumb, and that immediately afterwards he drinks a glassful of vinegar; by which he is thrown into a fit of laughter, terminating in convulsions and death.
With regard to the use of Antidotes, it has been already stated how little they are to be depended upon; in certain cases, however, we are bound to acknowledge their power, but they should be very rarely trusted, unless subsequent to, or in conjunction with, the operation of an emetic; in many cases the effects of this latter remedy may be promoted by the ingestion of liquids holding the particular antidote in solution, a practice which offers the double advantage of accelerating the elimination of the poison, and at the same time of decomposing any which may remain. Orfila has fully established the fact of Albumen being a counter-poison to Corrosive Sublimate;
Having ejected from the stomach all the poisonous matter we can by vomiting, and attempted to decompose what remains, we are to pursue such measures as may be calculated to prevent the absorption of the poison into the circulation; it has been already observed that on this account nauseating emetics should be avoided; the reader is now requested to refer to our exposÉ of the celebrated doctrine of Majendie, (page 86, note) and he will see that Venesection proves one of the most powerful means of exciting the function of absorption; hence in poisoning by arsenic, such an expedient should never be recommended,
3. To anticipate the occurrence of the Consecutive Phoenomena, and to combat them by appropriate treatment.
This is to be conducted on the general principles of Therapeutics; the treatment must necessarily vary in each particular case. Where the exhaustion of nervous energy is to be feared, as after poisoning by Prussic Acid, ammonia, and other diffusible stimulants, together with external warmth, will furnish the best resource; for the same reason Venesection should be performed with great caution and judgment after a narcotic poison. Where, on the other hand, inflammatory action is to be anticipated, it is unnecessary to detail the plan of treatment which may be adopted with the greatest chance of success. In cases where the nervous system is stupified, the symptoms may be combated by vegetable acids, infusion of coffee, &c. but where it is in a state of prÆternatural excitement, recourse must be had to opiates.
ESCHAROTICS:
Substances whose application to the animal solids, erodes, or decomposes them.
Their surgical value consists in their power to remove excrescencies, to establish an ulcer, or to convert an ulcerated surface into a simple sore.
IV. OF MECHANICAL REMEDIES.
This subdivision includes those classes of remedies, whose operation depends entirely upon mechanical principles; and we must agree with Dr. Murray in considering them as the least important of all the articles which we have enumerated, and which cannot therefore constitute objects of elaborate inquiry.
ANTHELMINTICS:
Remedies which expel worms
It has been already stated, (page 90) that certain bodies have the power of increasing the peristaltic motions of the intestinal canal, by operating as mechanical stimulants upon its fibres; in this manner the filings of tin and iron, or the irritating down which covers the pods of the Dolichos Pruriens, are supposed to act in dislodging and evacuating the worms from the intestines. But there is a variety of remedies employed as vermifuges, which must owe their effects to a very different mode of operation; Bitters for instance appear to prove an absolute poison
DEMULCENTS:
Medicines which are capable of shielding sensible surfaces from the action of acrid matter, by involving it in a mild and viscid medium.
It cannot be denied that where these remedies admit of direct application, considerable benefit may arise; in the progress of a catarrh, we have all experienced the relief that may be occasioned by lubricating the fauces with demulcents, which, by soothing the top of the trachea, quiets, by a kind of contiguous sympathy, the whole pulmonary structure; in certain states of intestinal irritation, the same remedies have furnished considerable benefit, and in ophthalmia, relief has been obtained by the application of a demulcent to the inflamed conjunctiva, by which it is defended from the irritation of the tears; see also Formula 61; but in parts beyond the reach of the first passages, and to which no fluid can arrive but through the medium of the secretions, it is very difficult to explain the principle upon which their beneficial operation can depend; and it seems indeed highly probable that they act in such cases as simple diluents, for the process of digestion must necessarily deprive them of their characteristic viscidity. The administration of demulcent drinks in gonorrhÆa is probably of no farther service in assuaging the ardor urinÆ, than an equivalent quantity of pure water; although Dr. Murray observes, “it is sufficiently certain, that many substances, which undergo the process of digestion, are afterwards separated in their entire state from the blood, by particular secreting organs; and there is, continues he, no gland which has this power more particularly than the kidneys; substances received into the stomach and digested, afterwards passing off in the urine with all their peculiar properties.” This is undoubtedly very true, but mucilaginous substances rarely or never pass off in this manner; if they evade the assimilative functions, they pass through the alimentary canal, and are thus eliminated. I can state, as the result of experiment, that the urine undergoes no change except in the relative proportion of its water, by the copious and repeated administration of mild mucilages. Dr. Saunders has very justly remarked that the long list of Ptisans, Decoctions, &c. usually prescribed upon these occasions, generally owe their virtues to the watery diluent itself.
The pharmaceutical applications of this class of medicines constitute, perhaps, not the least part of their value, by which we are enabled to introduce acrid substances into the stomach with safety and effect; but such services will more properly fall under our notice in a future part of the work.
DILUENTS:
Watery liquors, which increase the fluidity of the blood, and render several of the secreted and excreted fluids less viscid.
There are certainly few remedies whose operation is more simple, obvious,
It is here necessary to say a few words upon the misapplication of this order of remedies. Dr. Davy found by experiment that when an animal is bled to death, the last portions of blood that flow are of a much lower specific gravity than that which flows first, in consequence of the former containing more water, which it may be inferred was derived by the increased activity of the absorbents, exerted chiefly on mucous and serous membranes. Since then venesection promotes and accelerates absorption,
In the use of water upon such occasions, it may moreover be observed, that its temperature ought to be attended to; as a general rule it may be
With regard to the value of diluents, as capable of promoting the operation of other remedies, many observations of great practical importance might be adduced; but this subject will be more properly elucidated when we come to consider the influence of solubility in modifying the activity of medicinal substances, and which constitutes a very curious and interesting object of chemico-medical enquiry.
While speaking of Diluents it may be cursorily noticed, that water appears, under certain circumstances of the body, to suffer decomposition, and to have its elements appropriated to new combinations. Count Rumford has endeavoured to prove, that the surprisingly small quantity of solid food which is sufficient for nourishment, when converted into rich and palatable soup, is owing to the culinary process having prepared the water for chemical decomposition,
EMOLLIENTS:
Substances whose application diminishes the force of cohesion in the particles of the solid matter of the human body, and thereby renders them more lax and flexible.
According to this definition, which we derive from Dr. Cullen, the primary operation of emollients would appear to be purely mechanical, for they are insinuated into the matter of the solid fibre, and either diminish its density, or lessen the friction between its particles; this explanation will undoubtedly apply to those emollients which consist of unctuous bodies, and which are introduced into the animal fibre by friction; but it is evident that the beneficial effects of Cataplasms and Fomentations cannot be so explained; for in these instances, none of the materials can be absorbed through the entire cuticle; and yet the relaxation and consequent ease which such warm applications produce on inflamed surfaces is very considerable, but it must be wholly attributed to the relaxing effects of warmth and moisture upon the extreme vessels of the surface, propagated by contiguous sympathy to the deeper seated organs.
The operation of those substances which afford relief to excoriated surfaces by their bland qualities, as mucilaginous lotions in erysipelatous affections, is too obvious to require explanation.
Having thus investigated the manner in which medicinal substances produce their effects upon the living system, we shall be better prepared to appreciate the advantages which are to be derived from their combination with each other, and to escape the too common error of uniting in one formula, remedies which are rendered adverse by the incompatibility of their physiological actions.
