As agriculture promises food to the healthy, so medicine promises health to the sick. There is no place in the world, where this art is not found: for even the most barbarous nations are acquainted with herbs, and other easy remedies for wounds and diseases. However it has been more improved by the Greeks than any other people: though not from the infancy of that nation, but only a few ages before our own times; as appears by their celebrating Æsculapius as its most ancient author; who, because he cultivated this science with somewhat more accuracy, which, before him, was rude and of low esteem, was received into the number of their gods.(1) After him his two sons, Podalirius and Machaon, following Agamemnon to the Trojan war, were not a little useful to their fellow soldiers. But even these, according to Homer’s account, did not undertake the plague, nor the other various kinds of diseases, but only cured wounds by incisions, and medicines: from which it appears, that they entirely confined themselves to the chirurgical part of medicine, and that this was the most antient branch. From the same author we may also learn, that diseases were then believed to arise from the anger of the immortal gods,(2) and that relief used to be sought from them. It is also probable, that though there were few remedies for distempers known, men nevertheless generally enjoyed good health from the sobriety of their lives, yet untainted by sloth and luxury. For these two vices, first in Greece, and then among us, rendered men liable to many diseases. And hence that variety of remedies now used, which was neither necessary in ancient times, nor is yet in other nations, scarcely protracts the lives of a few of us to the verge of old age. For the same reason, after those, whom I have mentioned, no men of eminence practised medicine, till learning began to be pursued with greater application; which, as it is of all things most necessary to the mind, so it is no less hurtful to the body. And at first the science of healing was accounted a branch of philosophy; so that the cure of diseases, and the study of nature, owed their rise to the same persons: and for this very good reason, because they, who had impaired their bodies by anxious thought, and nightly watchings, stood most in need of its assistance. And thus we find, that many amongst the philosophers were skilled in this science; of whom the most celebrated were Pythagoras, Empedocles, and Democritus. Hippocrates of Cos, who, according to some authors, was the disciple of the last mentioned of these, and is so justly admired both for his knowledge in this profession, and for his eloquence, was the first worthy of notice, who separated medicine from the study of philosophy. After him, Diocles the Carystian, then Praxagoras and Chrysippus; after these, Herophilus and Erasistratus applied themselves to this art, and differed widely from each other in their methods of cure.

(1) For references 1, 2, 3, &c. see Notes at the end.

During this period, physick was divided into three parts: the first cured by diet, the second by medicines, the third by manual operations: the first they termed, in Greek, DiÆtetice,[ X ] the second Pharmaceutice,[ Y ] and the third Chirurgice.[ Z ] The most illustrious professors of that branch, which treats diseases by diet, endeavoured to extend their views farther, and took in the assistance of natural philosophy; being persuaded that, without it, medicine would be a weak and imperfect science. After these came Serapion, who first of all maintained, that the rational method of study was foreign to the art of medicine, and confined it to practice and experience. In his steps followed Appollonius and Glaucias, and some time after Heraclides of Tarentum, and others of no small note; who, from the doctrine they asserted, stiled themselves Empiricks[ AA ]. And thus the Dietetick branch was also divided into two parts, one set of physicians pursuing theory, the other following experience alone. However, after these we have enumerated above, no one attempted any thing new, till Asclepiades, who greatly changed the art of medicine. And Themison, one of his successors, has also lately, in his old age, departed from him in some things. And these are the men, to whom we are chiefly indebted for the improvements made in this salutary profession.

As that branch of medicine, which respects the cure of diseases, is the noblest, as well as the most difficult of the three, we shall first treat of that part. And because in this the chief dispute is, that some alledge an acquaintance with experiments to be only requisite, while others affirm experience alone to be insufficient, without a thorough knowledge of the constitution of bodies, and what naturally happens to them; it will be proper to recite the principal arguments on both sides, that we may the more easily deliver our own opinion upon the question.

Those then, who declare for a theory in medicine, look upon the following things as necessary: the knowledge of the occult and constituent causes of distempers; next, of the evident ones; then, of the natural actions; and, lastly, of the internal parts. They call these causes occult, in which we inquire of what principles our bodies are composed, what constitutes health, and what sickness. For they hold it impossible that any one should know how to cure diseases, if he be ignorant of the causes, whence they proceed; and that it is not to be doubted, but one method of cure is required, if the redundancy or deficiency in any of the four principles(3) be the cause of diseases, as some philosophers have affirmed; another, if the fault lie wholly in the humours, as Herophilus thought; another, if in the inspired air, as Hippocrates believed; another, if the blood be transfused into those vessels(4), which are designed only for air, and occasion an inflammation, which the Greeks call phlegmone[ AB ], and that inflammation cause such a commotion as we observe in a fever, which was the opinion of Erasistratus; another, if the corpuscles passing through the invisible pores should stop, and obstruct the passage, as Asclepiades maintained: that he will proceed in the proper method of curing a disease, who is not deceived in its original cause. Nor do they deny experience to be necessary, but affirm, it cannot be obtained without some theory; for that the more ancient practitioners did not prescribe any thing, at hazard, for the sick, but considered what was most suitable, and examined that by experience, to which they had before been led by some conjecture. That it is of no moment in this argument, whether most remedies were discovered by experiment, provided they were at first applied with some rational view: and that this holds in many cases; but new kinds of distempers often occur, in which practice has hitherto given no light; so that it is necessary to observe whence they arose; without which no mortal can find out, why he should make use of one thing, rather than another. And for these reasons they investigate the occult causes. They term those causes evident, in which they inquire, whether the beginning of the distemper was occasioned by heat or cold, fasting or surfeit, and the like. For they say, he will be able to oppose the first appearances, who is not ignorant of their rise. Those actions of the body which they call natural, are inspiration and exspiration, the reception and concoction of our meat and drink, as also the distribution(5) of the same into the several parts of the body. They also inquire how it happens, that our arteries rise and fall; from what causes proceed sleep and watching; without the knowledge of which, they conceive it impossible for any person either to oppose the beginnings of diseases, that depend on these particulars, or cure them when formed. As of all these things they look upon concoction to be of the greatest importance, they insist chiefly upon it; and some of them following the opinion of Erasistratus, affirm that the food is concocted in the stomach by attrition; others, after Plistonicus, the disciple of Praxagoras, by putrefaction; others, upon the credit of Hippocrates, believe concoction is effected by heat. After them follow the disciples of Asclepiades, who hold all these hypotheses to be vain and idle; for that there is no concoction at all, but the matter, crude as it is received, is distributed through the whole body. And in these things they are by no means agreed: however, it is not disputed, that according to the different hypotheses, a different regimen of diet is to be observed by sick people. For if it be performed by attrition, such food is to be chosen, as will most easily be broken to pieces; if by putrefaction, such as most quickly undergoes that change; if heat be the cause of concoction, then such as most effectually cherishes heat. But if there be no concoction at all, then none of these kinds of aliment are to be chosen: but such are to be taken, as are least liable to change from the state in which they are received. And, by the same way of reasoning, when there is a difficulty of breathing, when sleep or watchings oppress, they are of opinion, that the man, who has first learned in what manner these happen, will be capable of curing them. Besides, as pains, and various other disorders, attack the internal parts, they believe no person can apply proper remedies to those parts, which he is ignorant of; and therefore, that it is necessary to dissect dead bodies, and examine their viscera and intestines; and that Herophilus and Erasistratus had taken far the best method for attaining that knowledge, who procured criminals out of prison, by royal permission, and dissecting them alive, contemplated, while they were even breathing, the parts, which nature had before concealed; considering their position, colour, figure, size, order, hardness, softness, smoothness, and asperity(6); also the processes and depressions of each, or what is inserted into, or received by another part; for, say they, when there happens any inward pain, a person cannot discover the seat of that pain, if he have not learned where every viscus or intestine is situated; nor can the part, which suffers, be cured by one, who does not know what part it is; and that when the viscera happen to be exposed by a wound, if one is ignorant of the natural colour of each part, he cannot know what is sound and what corrupted; and for that reason is not qualified to cure the corrupted parts; besides they maintain, that external remedies are applied with much more judgment, when we are acquainted with the situation, figure, and size of the internal parts; and that the same reasoning holds in all the other instances above mentioned. And that it is by no means cruel, as most people represent it, by the tortures of a few guilty, to search after remedies for the whole innocent race of mankind in all ages.

On the other hand, those, who from experience, stile themselves empiricks, admit indeed the evident causes as necessary; but affirm the inquiry after the occult causes and natural actions to be fruitless, because nature is incomprehensible. And that these things cannot be comprehended, appears from the controversies among those, who have treated concerning them, there being no agreement found here either amongst the philosophers or the physicians themselves: for, why should one believe Hippocrates rather than Herophilus? or, why him more than Asclepiades? that if a man inclines to determine his judgment by reasons assigned, the reasons of each of them seem not improbable; if by cures, all of them have restored the diseased to health; and therefore we should not deny credit either to the arguments or authority of any of them. That even the philosophers must be allowed to be the greatest physicians, if reasoning could make them so; whereas it appears, that they have abundance of words, and very little skill in the art of healing. They say also that the methods of practice differ according to the nature of places; thus one method is necessary at Rome, another in Egypt, and another in Gaul. That if the causes of distempers were the same in all places, the same remedies ought also to be used every where. That often too the causes are evident; as for instance in a lippitude(7), or a wound, and nevertheless the method of cure does not appear from them: that if the evident cause does not suggest this knowledge, much less can the other, which is itself obscure. Seeing then this last is uncertain and incomprehensible, it is much better to seek relief from things certain and tried; that is, from such remedies as experience in the method of curing has taught us, as is done in all other arts; for that neither a husbandman nor a pilot is qualified for his business by reasoning, but by practice: and that these disquisitions have no connection with medicine, may be inferred from this plain fact, that physicians, whose opinions in those matters have been directly opposite to one another, have notwithstanding equally restored their patients to health: that their success was to be ascribed to their having derived their methods of cure, not from the occult causes, or the natural actions, about which they were divided, but from experiments, according as they had succeeded in the course of their practice. That medicine, even in its infancy, was not deduced from these inquiries, but from experiments: for of the sick, who had no physicians, some from a keen appetite, had immediately taken food in the first days of their illness, while others feeling a nausea, had abstained from it; and that the disorder of those, who had abstained, was more alleviated; also, some in the paroxysm of a fever had taken food, others a little before it came on, and others after its remission; and that it succeeded best with those who had done it after the removal of the fever: in the same manner some used a full diet in the beginning of a disease; others were abstemious; and that those grew worse, who had eaten plentifully. These and the like instances daily occurring, that diligent men observed attentively, what method generally answered best, and afterwards began to prescribe the same to the sick. That this was the rise of the art of medicine, which by the frequent recovery of some, and the death of others, distinguishes what is pernicious from what is salutary; and that when the remedies were found, men began to discourse about the reasons of them: that medicine was not invented in consequence of their reasoning, but the theory was sought for after the discovery of medicine. They ask too, whether reason prescribes the same as experience, or something different; if the same, they infer it to be needless, if different, mischievous. That at first, however, there was a necessity for examining remedies with the greatest accuracy, but now they are sufficiently ascertained; and that we neither meet with any new kind of disease, nor want any new method of cure. That if some unknown distemper should occur, the physician would not therefore be obliged to have recourse to the occult things; but he would presently see to what distemper it is most nearly allied, and make trial of remedies like to those, which have often been successful in a similar malady, and by the resemblance between them would find some proper cure. For they do not affirm, that judgment is not necessary to a physician, and that an irrational animal is capable of practising this art; but that those conjectures, which relate to the occult things, are of no use; because it is no matter what causes, but what removes a distemper: nor is it of any importance in what manner the distribution is performed, but what is most easily distributed; whether concoction fails from this cause or that; or whether it be properly a concoction, or only a distribution: nor are we to inquire how we breathe, but what relieves a difficult and slow breathing; nor what is the cause of motion in the arteries, but what each kind of motion indicates. That these things are known by experience: that in all disputes of this kind, a good deal may be said on both sides; and therefore genius and eloquence obtain the victory in the dispute; but diseases are cured not by eloquence, but by remedies; so that if a person, without any eloquence, be well acquainted with those remedies, that have been discovered by practice, he will be a much greater physician than one who has cultivated his talent in speaking without experience. That these things, however, which have been mentioned, are only idle: but what remains is also cruel, to cut open the abdomen and prÆcordia of living men, and make that art, which presides over the health of mankind, the instrument, not only of inflicting death, but of doing it in the most horrid manner; especially if it be considered, that some of those things, which are sought after with so much barbarity, cannot be known at all, and others may be known without any cruelty; for that the colour, smoothness, softness, hardness, and such like, are not the same in a wounded body, as they were in a sound; and further, because these qualities, even in bodies that have suffered no external violence, are often changed by fear, grief, hunger, indigestion, fatigue, and a thousand other inconsiderable disorders; which makes it much more probable, that the internal parts, which are far more tender, and never exposed to the light itself, are changed by the severest wounds and mangling. And that nothing can be more ridiculous than to imagine any thing to be the same in a dying man, nay one already dead, as it is in a living person: for that the abdomen(8) indeed may be opened(9), while a man breathes; but as soon as the knife has reached the prÆcordia(10), and the transverse septum is cut, which by a kind of membrane divides the upper from the lower parts, (and by the Greeks is called the Diaphragm[ AC ]) the man immediately expires; and thus the prÆcordia, and all the viscera never come into the view of the butchering physician, till the man is dead; and they must necessarily appear as those of a dead person, and not as they were while he lived; and thus the physician gains only the opportunity of murdering a man cruelly, and not of observing, what are the appearances of the viscera in a living person: if, however, there be any thing which can be observed in a person, that yet breathes, chance often throws it in the way of such as practise the healing art; for that sometimes a gladiator on the stage, a soldier in the field, or a traveller beset by robbers, is so wounded, that some internal part, different in different people, may be exposed to view; and thus a prudent physician finds their situation, position, order, figure, and the other particulars he wants to know, not perpetrating murder, but attempting to give health; and learns that, by compassion, which others had discovered by horrid cruelty. That for these reasons it is not necessary to lacerate even dead bodies; which, though not cruel, yet may be shocking to the sight, since most things are different in dead bodies; and even the dressing of wounds shows all that can be discovered in the living.

Since these points have often been, and still continue to be disputed with great warmth by physicians in large volumes, ’tis proper to add some reflections, that may seem to come the nearest to the truth, and which neither slavishly follow either of these opinions, nor are too remote from both, but lie, as it were, in the middle, betwixt these opposite extremes; which those, that inquire after truth without partiality, may find to be the surest method for directing the judgment in most warm controversies, as well as in this now before us. For, with regard to the causes of health or diseases, in what manner the air, or food, is either conveyed or distributed, the philosophers themselves do not attain to an absolute certainty; they only make probable conjectures. Now, when there is no certain knowledge of a thing, a mere opinion about it cannot discover a sure remedy. And it must be owned, that nothing is of greater use, even to the rational method of curing, than experience. Altho’ then many things are taken into the study of arts, which do not, properly speaking, belong to the arts themselves, yet they may greatly improve them by quickening the genius of the artist; wherefore the contemplation of nature, though it cannot make a man a physician, yet may render him fitter for the practice of medicine. Indeed, it is very probable, that both Hippocrates and Erasistratus, and all the others, who were not content with treating fevers and ulcers, but examined in some measure into the nature of things, tho’ they did not by such study become physicians, yet became more able physicians by that means. And medicine itself requires the help of reason, if not always amongst the occult causes, or the natural actions, yet often; for it is a conjectural art; and not only conjecture in many cases, but even experience is found not consistent with its rules. And sometimes neither fever, nor appetite, nor sleep, follow their usual antecedents in the regular course. A new distemper sometimes, though very seldom, appears; that such a case never happens is manifestly false; for, in our own time, a certain lady, from a quantity of flesh(11) falling down from her private parts, and growing dry, expired in a few hours; so that the most celebrated physicians neither found out the genus of the distemper, nor any remedy for it. I suppose the reason they forbore to attempt any thing was, that none of them was willing to run a risk upon his own conjecture only in a person of her quality, for fear he should be thought to have killed, if he did not save her; yet it is probable that some one, without that regard to the opinion of the world, might have contrived something, which upon trial would have succeeded. Nor is a similitude always serviceable in this kind of practice; and where it is, this properly belongs to the rational part, to consider amidst a number of similar kinds, both of diseases and remedies, what particular medicine ought to be preferred. When such an incident occurs, the physician ought to invent something, which though perhaps it does not always answer, yet most commonly may: and he shall draw his new method, not from the occult things (for they are dubious and uncertain) but from those, that can be fully known, that is, from the evident causes. For it makes a considerable difference, whether the distemper was occasioned by fatigue, or thirst, or cold, or heat, or watching, or hunger; or whether it arose from too much food and wine, or excess of venery. And he ought not to be ignorant of the constitution of his patient, whether his body be too moist, or too dry: whether his nerves(12) be strong or weak; whether he be frequently or seldom ailing; and whether his illnesses are severe or slight, of long continuance or short; what way of life he has pursued, laborious or sedentary, luxurious or frugal; for from these, and such like circumstances, he must often draw a new method of cure.

Nevertheless even these things ought not to be so passed over, as if they were uncontroverted; for Erasistratus has affirmed, that distempers were not occasioned by them, because other people, and even the same person at different times, would not fall into a fever upon them. And some of the Methodists of our own age, from the authority of Themison (as they would have it thought) assert, that the knowledge of no cause whatever bears the least relation to the method of cure; and that it is sufficient to observe some general symptoms of distempers; and that there are three kinds of diseases, one bound, another loose(13), and the third a mixture of these. For that sometimes the excretions of sick people are too small, sometimes too large; and sometimes one particular excretion is deficient, while another is excessive. That these kinds of distempers are sometimes acute, and sometimes chronic; sometimes increasing, sometimes at a stand(14), and sometimes abating. As soon then as it is known, to which of these classes a distemper belongs if the body be bound, it must be opened; if it labours under a flux, it must be restrained; if the distemper be complicated, then the most urgent malady must be first opposed. And that one kind of treatment is required in acute, another in inveterate distempers; another, when diseases are increasing; another, when at a stand; and another, when inclining to health. That the observation of these things constitutes the art of medicine, which they define as a certain way of proceeding, which the Greeks call Method[ AD ], and affirm it to be employed in considering those things, that are in common to the same distempers: nor are they willing to have themselves classed either with the rationalists, or with those, who regard only experiments; for they dissent from the first sect, in that they will not allow medicine to consist in forming conjectures about the occult things; and also from the other in this, that they hold the observation of experiments to be a very small part of the art.

As to what Erasistratus maintains; in the first place, plain fact contradicts his opinion; because a distemper very seldom happens, unless after some of these occurrences, that have been mentioned. And then it does not follow, that what does not affect one person, may not hurt another; nor what does not affect the same person at one time, may not hurt him at another; for there may be some latent circumstances in a body, either in respect of weakness, or some disorder, which either are not in another, nor were in the same body at a different time; and these, though of themselves not considerable enough to cause a distemper, yet may render a body more liable to other injuries: but if he had been sufficiently skilled in the contemplation of the works of nature (which the physicians with very good reason endeavour to attain) he must have known this also, that nothing happens from one single cause; but that is to be taken for the cause, which seems to have contributed most to the effect. Now it is possible, that what does not move at all while alone, may in conjunction with other things excite a great commotion. Besides, Erasistratus himself, who says, that a fever arises from a transfusion of the blood into the arteries, and that this happens in a plethoric body, can assign no reason, why of two persons equally plethoric, the one should fall into a distemper, and the other be free from all danger, which manifestly happens every day. From hence it appears, that supposing this transfusion to be real, nevertheless, when there is a plethora, it does not happen of itself, but when some one of the conditions above-mentioned goes along with it.

But the followers of Themison, if they assert their maxims to hold universally, are still more rationalists than those, that pass under that name; for though one rationalist does not maintain all that another approves, there is no necessity to invent a new appellation for him; provided, which is the principal thing, he does not proceed upon memory alone, but takes in reason too. But if, which is nearer to the truth, the art of medicine hardly admits of any universal precepts, then they are in the same class with those, who depend upon experiments alone: and the more so, because any unskilful person can discover, whether a distemper has bound up a man, or rendered him lax. Now if what relaxes a constringed body, or restrains a loose, be drawn from reason, such a practitioner is a rational physician: but if from experience, as he must confess, who will not allow himself to be a rationalist, then he is an empirick. And so, according to him, the knowledge of the distemper is foreign to the art, but the remedy lies within the bounds of experience. Nor is any improvement made by them upon the profession of the empiricks, but on the contrary, something is taken from it; the empiricks attending with great circumspection to many circumstances; whereas these regard only the easiest, and no more than the common things. For in like manner those, who are employed in curing cattle, since it is impossible for them to be informed by the dumb animals, what is peculiar in the case of each, regard only what is common to them all: and foreign nations, as they are not acquainted with any subtile theory of medicine, take notice only of the common symptoms: those also, who take under their care a great number of patients, because they are not able to consult the distinct necessities of each with the utmost attention, have respect only to those generals. Nor indeed were the ancient physicians ignorant of this method, but they were not content with it; for even the most ancient writer Hippocrates said, that in practice it is necessary to regard both the general and peculiar circumstances. Nor is it possible even for them to confine themselves within the narrow limits of their own profession; for there are different kinds both of the bound, and lax disorders; which is more easily observed in the lax, for it is one thing to vomit blood, another to vomit bile, and another to vomit the food: and there is also a difference betwixt labouring under a simple purging, and a dysentery; between being weakened by sweats, and wasted by a consumption. A humour also breaks out upon particular parts, as the eyes, for instance, and the ears; and no member of the human body is free from that danger. Now not one of these disorders is cured exactly in the same manner as another; so that in these, medicine descends from the general observation of the lax kind, to the peculiar. And in this again another kind of knowledge of peculiarity is often necessary; because the same thing will not relieve all, that labour under similar distempers. For though there are certain things, which either bind the belly, or open it in most people; yet some are to be met with, in whom the same intention is gained by means contrary to the common. So that in such, the general observation is hurtful, and the peculiar only salutary. And a right apprehension of the cause often removes a distemper. Upon this account it was, that the most ingenious physician of our age, the late Cassius, being called to one in a fever distressed with violent thirst, when he found, that his complaints began after hard drinking, ordered him to drink plentifully of cold water. When his patient had drank this, and by the mixture had weakened the force of the wine, he was presently freed from the fever by a sleep, and a sweat. Which remedy the physician very judiciously adapted to the case, not from the consideration of his body being either bound or loose, but from the cause that had preceded. There is also another peculiarity to be regarded, which is that of place and season, according to these authors themselves; who, when they are giving directions for the management of the healthy, order them more carefully to avoid cold, heat, satiety, labour, and venery, in sickly places or seasons; and to take more rest in such seasons or places, if they have any sense of weight hanging upon their body; and in such circumstances neither to disturb the stomach by vomiting, nor the belly by purging. These things indeed are certain; yet they descend from generals to some things that are particular: unless they would have us believe, that healthy men should observe the temper of the air, and the season of the year, and that sick people don’t need to take that care, to whom all precaution is so much the more necessary, by how much an infirm state of health is more liable to receive injury. Besides, there are very different properties of distempers in the same person. And one, who has been sometimes unsuccessfully tried by medicines, which seemed proper for his disorder, is often recovered by the contrary. There are also many distinctions to be observed in the giving of food, of which I shall only name one instance. A youth bears hunger more easily than a boy; better in a thick, than a clear air; more easily in winter than summer; with more ease, one, that is accustomed to a single meal, than another, who eats a dinner also(15); a sedentary person more easily, than one that takes exercise. Now generally food ought to be prescribed so much the sooner, as the person is less able to bear the want of it in health. For these reasons I am apt to think, that he, who is not acquainted with the peculiarities, ought only to consider the general: and that he, who can find out the peculiar, ought not to neglect, but take them in too for the direction of his practice. And therefore, where the knowledge is equal, yet a friend is a more useful physician, than a stranger. To return to my point then, my opinion is, that medicine ought to be rational, but to draw its methods from the evident causes, all the obscure being removed, not from the attention of the artist, but from the practice of the art. Again, to dissect the bodies of living men is both cruel and superfluous. But the dissection of dead subjects is necessary for learners: for they ought to know the position and order of the parts, which dead bodies will show better, than a living and wounded man. But as for the other things, which can only be observed in living bodies, practice itself will discover them in the cure of the wounded, somewhat more slowly, but with more tenderness. Having delivered my sentiments upon these points, I shall lay down the proper rules for the management of people in health, and then proceed to what relates to diseases and their cure.

CHAP. I. RULES FOR THE HEALTHY.