PART II.

CRITICAL ANALYSIS.

I.

Du Degré de Certitude de la Médecine. Par P. J. G. CABANIS, Membre du Senat Conservateur de l'Institut National, de l'Ecole et Societé de Médecine de Paris, &c. Nouvelle Edition; revue, corrigée, et augmentée de plusieurs autres ecrits du même auteur. A Paris. 1805.

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HERE is no want of essays on the speculative parts of medicine, but there is a great deficiency of faith and enthusiasm for the improvement of the practical parts. The fondness for theory has subsided, and an opposite spirit of sceptical indifference seems to have taken hold of most mens minds; for, in the late bustle about medical reform, not a word has been said about reforming the modes of practice; it seems to be taken for granted, that the method of curing diseases is well understood, and that it is only necessary for persons to go to the proper schools long enough to learn their lessons. Now, in order to study and to practise medicine as it ought, we must consider it as an object of importance; and the first requisite for attaching the true degree of importance to it, is to believe that it is founded in nature and truth. If the art itself has a solid basis like other arts and sciences, if it can be useful, if the consolations it affords are necessary to the unfortunate sufferer, if it be the interest and the duty of the public to encourage and watch over its labours, too many incitements cannot be employed to lead young men, who are destined for the practice of physic, to devote themselves entirely to it, to make them feel all the dignity of their office, and to inspire them with zeal in the pursuit. Such was the object of M. Cabanis in composing this little essay on the degree of certainty belonging to medical science; and we think it is better calculated to make good and conscientious practitioners, than long stories and stale jokes upon every part of the profes sion, if the times should ever become so degenerate as to retail these substitutes for practical precepts from professors chairs.

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Our author, in an introduction of some length, endeavours to demonstrate, that disease and death are the necessary consequences of the laws of the animal economy. Man, from his very constitution, is more subject to the causes of disease than the other animals, even if civil institutions and social customs did not expose him still more to many unhealthy impressions. The desire of prolonging life, and of avoiding pain, is as natural as to suffer and to die. Nature teaches us to change an uneasy posture, to apply the hand to painful parts, to relax the integuments by the application of gentle heat and moisture; she points out the necessity of repose, and removal from noise, as soon as the functions of our organs are disturbed by fever. Singular appetites, or longing for remarkable articles of food, which cannot be accounted for, often suggest the means requisite for recovery. In short, all our wants are changed into sufferings when they are not supplied; and as nature makes a declaration of this sort in the clearest manner, we may, as an ancient writer observed, give the name of a remedy to every thing that satisfies a want, and call instinct, or the cause of those spontaneous actions, the first of physicians. Although medicine, founded upon instinct, must necessarily be very limited in civilized life, because it is influenced by a crowd of ideas, passions, and prejudices, which do not disturb its operation in a simple state of society, yet it ought never to be lost sight of, although it is far from furnishing such enlightened directions as some enthusiastic writers have asserted. Passing over all the hypotheses concerning the natural state of mankind, the author takes man as he is in society, and sets out upon inquiring whether the principles of medical science can be shewn to rest upon a solid basis, by observation and plain reasons, deduced from experience, or if the reproaches cast upon the art by philosophers and the vulgar have any foundation?

The objections against the certainty of medicine may be reduced to the six following, which the author states, and then ingeniously endeavours to refute. Perhaps we may be thought to attach more weight to some of these refutations, from finding a confirmation of some opinions of our own, which were published in a former number of this Journal, long before this essay came into our hands. Indeed it is only till very lately that we met with it, although it has been published some time. If it had been known to us sooner, it would have afforded us additional motives for insisting upon those notions, when supported by the authority of such a writer as Cabanis.

The following is a brief statement of the reasons alleged by the detractors of medicine :

1st. The secret springs of life are hidden from observation, and

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we have no precise idea, either of the principle which animates our bodies, or of the means by which it exercises its influence. 2d. The nature and proximate causes of diseases are quite unknown.

3d. Diseases are so various, and so susceptible of complication, that no fixed rule can be drawn from the most accurate observations to enable us always to discover them; they undergo so many modifications from age, sex, temperament, climate, season, state of the atmosphere, accustomed regimen, occupation, and habitual complaints; and are influenced so much by habitual passions, and by the state of the mind, that it is impossible, amidst so many different causes, to discover what belongs to each case, to attribute to each phenomenon its just value and natural place, or to form a suitable plan of treatment; in short, to draw inferences so certain and so conclusive, as to be worthy of the importance of the art.

4th. The nature of the substances employed as remedies is mysterious; their mode of acting upon our bodies is still more obscure, and it seems as if we had no way of arriving at this knowledge.

5th. Medical experience is more difficult of attainment than a knowledge of diseases from observation, more doubtful even than the diagnosis and prognosis which it furnishes. The effect of a remedy may be determined by a multitude of causes which the physician cannot detect. The silent, yet constant operation of that vis medicatrix, always tending to re-establish order in organized bodies; the progress of the disease itself, whose nature may not be rightly understood; the changes produced in the physical or moral condition of the patient, or in the external circumstances around him; all these things are liable to impose on the severest judgment, to lead a physician to attribute his success to a series of combinations which are directly the reverse and here is evidently an inexhaustible source of error, both for the art itself, and for him who exercises it.

A cure follows the application of a remedy; the remedy therefore has produced the cure, "post hoc, ergo propter hoc. This is a specimen of very bad reasoning, undoubtedly; yet, by such a fallacious rule as this, all the articles of the materia medica have been classed, and the method of administering different remedies has been reduced to a system. Nothing demands ⚫ more enlightened understanding and caution than the discovery of truths of this kind: for, in inquiries after them, nothing is easier than to be led astray, even whilst pursuing the right path, nothing more uncertain than the proofs upon which the results

are

are supposed to rest, when we think we have obtained what are perfectly sure.

6th. If medicine was well founded, the theory would at all times be the same; the practice, too, would not differ in one age from another; ancient and modern physicians, men of all schools and all countries, would agree at least upon some important points; whereas, in running over the history of medical opinions, what a difference in their views, how contrary their methods of treatment !

Examination of the first objection.-It is acknowledged on the one hand, that the nature of the causes which move animated bodies is hidden from our researches, and, on the other, the circumstances which have a direct influence on its action in different organs, are equally unknown. If a knowledge of these were necessary to serve as the basis of the healing art, the art itself fails in its essential and fundamental part. The question, then, is reduced to this, to ascertain whether it be absolutely necessary, or, at least, whether it would be advantageous to penetrate into the essence of the vital powers, and to have a precise notion of their mode of operating upon the human body?

Man knows the essence of nothing: neither of matter, which is always before his eyes, nor of that secret principle which animates and determines all the phenomena of the universe. He often speaks of some causes which he flatters himself he has discovered, and of others which he laments his inability to find out; but the first causes are concealed from him as well as the very essence of things. He sees effects, or, rather, he receives sensations; he is constantly observing new relations; he arranges them in order to fix the recollection of them in his mind, to appreciate them better, and to draw from them what may contribute to his preservation, or afford him fresh enjoyment: this is the sum and substance of human knowledge. It is worth considering, how far the knowledge of first causes, in the pursuit of which so many profound lucubrations have been so uselessly expended, is really applicable to the wants of mankind. Is it necessary to understand what power balances the ocean, what primitive law directs this power to act with such regularity, in order to observe the regular course of the ebbing and flowing of the tides, for vessels to go down or ascend the mouth of a river? Is it necessary to understand the cause of affinity, elecricity, and cohesion of different bodies, in order to perform all the physical or chemical operations upon these properties? Must the secret cause of vegetable life be snatched from nature, must the instinctive and peculiar propensities of the plants be discovered, before agriculture can be invented, or brought to

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any degree of perfection? Certainly not. It has fallen to the lot of man to observe facts, and this is sufficient for him; he knows nothing of the nature of causation. We are ignorant of the cause of digestion; yet we are not less attracted by involuntary desires towards those substances most serviceable for food. By observing the different effects produced by different articles of diet, and by comparing those in different individuals, with our own experience, we endeavour to draw rules for dietetics, such, for example, as those which we owe to the genius of Hippocrates. Medicine is founded upon the same basis as dietetics, the subjects of observation are of the same nature, and the manner of proceeding to draw practical inferences is precisely the same in both cases. Whoever acknowledges the character of certainty in one of these instances, cannot place the other among hypothetical conjecture. Medicine, indeed, must have preceded dietetics, for the knowledge of regimen has been acquired by attending to the effects of food in diseases. It is not deemed necessary for dietetics to know the causes of digestion, in order to observe the facts belonging to that function; nor is it essential for medicine to understand the causes of animal life, in order to mark the deviations to which they are liable, or to know the means of restoring the deranged actions to their natural state. The phenomena of health and disease, the effects of aliments and of remedies, all come under the cognizance of our senses, and we draw rules from them which are necessary for the practice of the art. The first objection, therefore, is not well founded; as the want of knowing causes is not peculiar to medical science, if the reproach of uncertainty and conjecture can be applied to it with any truth; the principles of almost all the other sciences are exposed to the same charge.

Second objection.- In answering the first objection, the author conceives he has indirectly replied to the second, which only brings forward the same thing in other words. We are acquainted with the nature and causes of diseases, he says, such as facts manifest them to us. We know that fever produces certain changes, or rather, by these changes it shows itself to us; we can only determine its existence by them. When a man coughs, spits blood, breathes with difficulty, feels a pain in his side, has a quick and hard pulse, and his skin is hotter than natural, we say that he is attacked with a pleurisy. What is a pleurisy? You will be told, it is a disorder in which all or most of these circumstances are combined. If one or more of these be wanting, it is not a pleurisy, at least not the true pleurisy of the schools; therefore, it is the concurrence of these circumstances which constitute the disease. The word pleurisy only retraces them in an abridged