History of Civilization in England, Vol. 2 of 3

by Henry Thomas Buckle

The other discovery, of which the application is much more extensive, was made in exactly the same way. It consists of the striking fact, that the teeth of each animal have a necessary connexion with the entire organization of its frame; so that, within certain limits, we can predict the organization by examining the tooth. This beautiful instance of the regularity of the operations of nature was not known until more than thirty years after the death of Bichat, and it is evidently due to the prosecution of that method which he sedulously inculcated. For the teeth never having been properly examined in regard to their separate tissues, it was believed that they were essentially devoid of structure, or, as some thought, were simply a fibrous texture.[1103] But by minute microscopic investigations, it has been recently ascertained that the tissues of the teeth are strictly analogous to those of other parts of the body;[1104] and that the ivory, or dentine, as it is now called,[1105] is highly organized; that it, as well as the enamel, is cellular, and is, in fact, a development of the living pulp. This discovery, which, to the philosophic anatomist, is pregnant with meaning, was made about 1838; and though the preliminary steps were taken by Purkinjé, Retzius, and Schwann, the principal merit is due to Nasmyth and Owen,[1106] between whom it is disputed, but whose rival claims we are not here called upon to adjust.[1107] What I wish to observe is, that the discovery is similar to that which we owe to Agassiz; similar in the method by which it was worked out, and also in the results which have followed from it. Both are due to a recognition of the fundamental maxim of Bichat, that the study of organs must be subordinate to the study of tissues, and both have supplied the most valuable aid to zoological classification. On this point, the service rendered by Owen is incontestable, whatever may be thought of his original claims. This eminent naturalist has, with immense industry, applied the discovery to all vertebrate animals; and in an elaborate work, specially devoted to the subject, he has placed beyond dispute the astonishing fact, that the structure of a single tooth is a criterion of the nature and organization of the species to which it belongs.[1108]

Whoever has reflected much on the different stages through which our knowledge has successively passed, must, I think, be led to the conclusion, that while fully recognizing the great merit of these investigators of the animal frame, our highest admiration ought to be reserved not for those who make the discoveries, but rather for those who point out how the discoveries are to be made.[1109] When the true path of inquiry has once been indicated, the rest is comparatively easy. The beaten highway is always open; and the difficulty is, not to find those who will travel the old road, but those who will make a fresh one. Every age produces in abundance men of sagacity and of considerable industry, who, while perfectly competent to increase the details of a science, are unable to extend its distant boundaries. This is because such extension must be accompanied by a new method,[1110] which, to be valuable as well as new, supposes on the part of its suggester, not only a complete mastery over the resources of his subject, but also the possession of originality and comprehensiveness,—the two rarest forms of human genius. In this consists the real difficulty of every great pursuit. As soon as any department of knowledge has been generalized into laws, it contains, either in itself or in its applications, three distinct branches; namely, inventions, discoveries, and method. Of these, the first corresponds to art; the second to science; and the third to philosophy. In this scale, inventions have by far the lowest place, and minds of the highest order are rarely occupied by them. Next in the series come discoveries; and here the province of intellect really begins, since here the first attempt is made to search after truth on its own account, and to discard those practical considerations to which inventions are of necessity referred. This is science properly so called; and how difficult it is to reach this stage, is evident from the fact, that all half-civilized nations have made many great inventions, but no great discoveries. The highest, however, of all the three stages, is the philosophy of method, which bears the same relation to science that science bears to art. Of its immense, and indeed supreme importance, the annals of knowledge supply abundant evidence; and for want of it, some very great men have effected absolutely nothing, consuming their lives in fruitless industry, not because their labour was slack, but because their method was sterile. The progress of every science is affected more by the scheme according to which it is cultivated, than by the actual ability of the cultivators themselves. If they who travel in an unknown country, spend their force in running on the wrong road, they will miss the point at which they aim, and perchance may faint and fall by the way. In that long and difficult journey after truth, which the human mind has yet to perform, and of which we in our generation can only see the distant prospect, it is certain that success will depend not on the speed with which men hasten in the path of inquiry, but rather on the skill with which that path is selected for them by those great and comprehensive thinkers, who are as the lawgivers and founders of knowledge; because they supply its deficiencies, not by investigating particular difficulties, but by establishing some large and sweeping innovation, which opens up a new vein of thought, and creates fresh resources, which it is left for their posterity to work out and apply.

It is from this point of view that we are to rate the value of Bichat, whose works, like those of all men of the highest eminence,—like those of Aristotle, Bacon, and Descartes,—mark an epoch in the history of the human mind; and as such, can only be fairly estimated by connecting them with the social and intellectual condition of the age in which they appeared. This gives an importance and a meaning to the writings of Bichat, of which few indeed are fully aware. The two greatest recent discoveries respecting the classification of animals are, as we have just seen, the result of his teaching; but his influence has produced other effects still more momentous. He, aided by Cabanis, rendered to physiology the incalculable service, of preventing it from participating in that melancholy reaction to which France was exposed early in the nineteenth century. This is too large a subject to discuss at present; but I may mention, that when Napoleon, not from feelings of conviction, but for selfish purposes of his own, attempted to restore the power of ecclesiastical principles, the men of letters, with disgraceful subserviency, fell into his view; and there began a marked decline in that independent and innovating spirit, with which during fifty years the French had cultivated the highest departments of knowledge. Hence that metaphysical school arose, which, though professing to hold aloof from theology, was intimately allied with it; and whose showy conceits form, in their ephemeral splendour, a striking contrast to the severer methods followed in the preceding generation.[1111] Against this movement, the French physiologists have, as a body, always protested; and it may be clearly proved that their opposition, which even the great abilities of Cuvier were unable to win over, is partly due to the impetus given by Bichat, in enforcing in his own pursuit the necessity of rejecting those assumptions by which metaphysicians and theologians seek to control every science. As an illustration of this I may mention two facts worthy of note. The first is, that in England, where during a considerable period the influence of Bichat was scarcely felt, many, even of our eminent physiologists, have shown a marked disposition to ally themselves with the reactionary party; and have not only opposed such novelties as they could not immediately explain, but have degraded their own noble science by making it a handmaid to serve the purposes of natural theology. The other fact is, that in France the disciples of Bichat have, with scarcely an exception, rejected the study of final causes, to which the school of Cuvier still adheres: while as a natural consequence, the followers of Bichat are associated in geology with the doctrine of uniformity; in zoology, with that of the transmutation of species; and in astronomy, with the nebular hypothesis: vast and magnificent schemes, under whose shelter the human mind seeks an escape from that dogma of interference, which the march of knowledge every where reduces, and the existence of which is incompatible with those conceptions of eternal order, towards which, during the last two centuries, we have been constantly tending.

These great phenomena, which the French intellect presents, and of which I have only sketched a rapid outline, will be related with suitable detail in the latter part of this work, when I shall examine the present condition of the European mind, and endeavour to estimate its future prospects. To complete, however, our appreciation of Bichat, it will be necessary to take notice of what some consider the most valuable of all his productions, in which he aimed at nothing less than an exhaustive generalization of the functions of life. It appears, indeed, to me, that in many important points Bichat here fell short; but the work itself still stands alone, and is so striking an instance of the genius of the author, that I will give a short account of its fundamental views.

Life considered as a whole has two distinct branches;[1112] one branch being characteristic of animals, the other of vegetables. That which is confined to animals is called animal life; that which is common both to animals and vegetables is called organic life. While, therefore, plants have only one life, man has two distinct lives, which are governed by entirely different laws, and which, though intimately connected, constantly oppose each other. In the organic life, man exists solely for himself; in the animal life he comes in contact with others. The functions of the first are purely internal, those of the second are external. His organic life is limited to the double process of creation and destruction: the creative process being that of assimilation, as digestion, circulation, and nutrition; the destructive process being that of excretion, such as exhalation and the like. This is what man has in common with plants; and of this life he, when in a natural state, is unconscious. But the characteristic of his animal life is consciousness, since by it he is made capable of moving, of feeling, of judging. By virtue of the first life he is merely a vegetable; by the addition of the second he becomes an animal.

If now we look at the organs by which in man the functions of these two lives are carried on, we shall be struck by the remarkable fact, that the organs of his vegetable life are very irregular, those of his animal life very symmetrical. His vegetative, or organic, life is conducted by the stomach, the intestines, and the glandular system in general, such as the liver and the pancreas; all of which are irregular, and admit of the greatest variety of form and development, without their functions being seriously disturbed. But in his animal life the organs are so essentially symmetrical, that a very slight departure from the ordinary type impairs their action.[1113] Not only the brain, but also the organs of sense, as the eyes, the nose, the ears, are perfectly symmetrical; and they as well as the other organs of animal life, as the feet and hands, are double, presenting on each side of the body two separate parts which correspond with each other, and produce a symmetry unknown to our vegetative life, the organs of which are, for the most part, merely single, as in the stomach, liver, pancreas, and spleen.[1114]

From this fundamental difference between the organs of the two lives, there have arisen several other differences of great interest. Our animal life being double, while our organic life is single, it becomes possible for the former life to take rest, that is, stop part of its functions for a time, and afterwards renew them. But in organic life, to stop is to die. The life, which we have in common with vegetables, never sleeps; and if its movements entirely cease only for a single instant, they cease for ever. That process by which our bodies receive some substances and give out others, admits of no interruption; it is, by its nature, incessant, because, being single, it can never receive supplementary aid. The other life we may refresh, not only in sleep, but even when we are awake. Thus we can exercise the organs of movement while we rest the organs of thought; and it is even possible to relieve a function while we continue to employ it, because, our animal life being double, we are able for a short time, in case of one of its parts being fatigued, to avail ourselves of the corresponding part; using, for instance, a single eye or a single arm, in order to rest the one which circumstances may have exhausted; an expedient which the single nature of organic life entirely prevents.[1115]

Our animal life being thus essentially intermittent, and our organic life being essentially continuous,[1116] it has necessarily followed that the first is capable of an improvement of which the second is incapable. There can be no improvement without comparison, since it is only by comparing one state with another that we can rectify previous errors, and avoid future ones. Now, our organic life does not admit of such comparison, because, being uninterrupted, it is not broken into stages, but when unchequered by disease, runs on in dull monotony. On the other hand, the functions of our animal life, such as thought, speech, sight, and motion, cannot be long exercised without rest; and as they are constantly suspended, it becomes practicable to compare them, and, therefore, to improve them. It is by possessing this resource that the first cry of the infant gradually rises into the perfect speech of the man, and the unformed habits of early thought are ripened into that maturity which nothing can give but a long series of successive efforts.[1117] But our organic life, which we have in common with vegetables, admits of no interruption, and consequently of no improvement. It obeys its own laws; but it derives no benefit from that repetition to which animal life is exclusively indebted. Its functions, such as nutrition and the like, exist in man several months before he is born, and while, his animal life not having yet begun, the faculty of comparison, which is the basis of improvement, is impossible.[1118] And although, as the human frame increases in size, its vegetative organs become larger, it cannot be supposed that their functions really improve, since, in ordinary cases, their duties are performed as regularly and as completely in childhood as in middle age.[1119]

Thus it is, that although other causes conspire, it may be said that the progressiveness of animal life is due to its intermittence; the unprogressiveness of organic life to its continuity. It may, moreover, be said, that the intermittence of the first life results from the symmetry of its organs, while the continuity of the second life results from their irregularity. To this wide and striking generalization, many objections may be made, some of them apparently insuperable; but that it contains the germs of great truths I entertain little doubt, and, at all events, it is certain that the method cannot be too highly praised, for it unites the study of function and structure with that of embryology, of vegetable physiology, of the theory of comparison, and of the influence of habit; a vast and magnificent field, which the genius of Bichat was able to cover, but of which, since him, neither physiologists nor metaphysicians have even attempted a general survey.

This stationary condition, during the present century, of a subject of such intense interest, is a decisive proof of the extraordinary genius of Bichat; since, notwithstanding the additions made to physiology, and to every branch of physics connected with it, nothing has been done at all comparable to that theory of life which he, with far inferior resources, was able to construct. This stupendous work he left, indeed, very imperfect; but even in its deficiencies we see the hand of the great master, whom, on his own subject, no one has yet approached. His essay on life may well be likened to those broken fragments of ancient art, which, imperfect as they are, still bear the impress of the inspiration which gave them birth, and present in each separate part that unity of conception which to us makes them a complete and living whole.