Part 3

In considering the application of physiology to the medical and surgical arts, a view of a new, simple and impressive natural system of medical science in general, and of its first principles as an art, will be exhibited; and rules will also be given for performing surgical operations with the utmost precision and ease, upon the principle of an invariable relation between the arrangement of internal, and the situation of certain external parts, which consequently form accurate signs of that arrangement.

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I may now observe, that the series of beings which the arrangement I have just delivered involves, all more or less evidence the phenomena of life and intellect, as well as exhibit structure, and I may conclude with a few observations concerning these phenomena.

Minerals have properly been said to exist, plants to exist and live, animals to exist, live and think.

These are all modifications of each other, as I shall afterwards shew; but, at present, I shall limit my observations to the two last of these classes, and to the additional phenomena, namely those of life and intellect, which they more strikingly exhibit.

I shall not, however, like some of the most celebrated modern physiologists, occupy my preliminary lectures with long details concerning their nature; but, as I reckon life to be the mere result of organization, I shall, throughout the course, illustrate it in connexion with those organs on which it depends, and shall, at present, only take a general view of its nature.

Life is a term which some philosophers have hitherto inaccurately employed as expressing an imaginary principle, though it merely designates a series of dependent actions. This they were doubtless induced to do by that artifice which has ever induced weak men to assume an air of knowledge by giving a particular name to what they did not understand; and the same artifice still induces such persons to blame those who endeavour to explain the phenomena of life according to obvious physical laws, precisely because a successful explanation would at once exhibit their ignorance and their desire to conceal it.

Life has, with equal absurdity, been termed a forced state, though it merely evinces a series of phenomena in justest unison with those of the universe. I dissent, therefore, from those who assert, that we employ the terms life and vital force to express what are apparent exceptions to general laws. This is only a repetition of the error of Brown. It was, however, an erroneous conclusion from accurate observations.

For example, says Cuvier, let us contemplate a female in the prime of youth and health,—that elegant voluptuous form—that graceful flexibility of motion—that gentle warmth—those cheeks crimsoned with the roses of delight—those brilliant eyes, darting rays of love, or sparkling with the fire of genius—that countenance enlivened by sallies of wit, or animated by the glow of passion, seem all united to form a most fascinating being. A moment is sufficient to destroy this illusion. Motion and sense often cease without any apparent cause; the body loses its heat; the muscles become flat; and the angular prominences of the bones appear; the lustre of the eye is gone; the cheeks and lips are livid.... These, however, are but preludes of change still more horrible. The flesh becomes successively blue, green and black. It attracts humidity; and while one portion evaporates in infectious emanations, another dissolves into a putrid sanies, which is also speedily dissipated. In a word, after a few short days, there remains only a small number of earthy and saline principles. The other elements are dispersed in air and in water to enter again into new combinations.

This, Cuvier adduces as a proof that the possession of life prevents the operation of external physical causes. The picture is perfectly correct, but the conclusion unauthorised.

It was indeed impossible for us not to feel the frequent necessity of deploring those we loved. We therefore thought that we perceived this principle operating when the evident influence of external causes, or some mysterious agency seemed to drive the noblest results of life, intellect and genius, from the philosopher and statesman, who had, by the diffusion of truth and resistance to arbitrary power, preserved the liberties, and aggrandized the happiness of nations; we thought we perceived their influence when imagination’s powers fled from the poet whose song had once almost conferred new life on the heroes of ancient times; we thought we perceived their influence when the phenomena of vital action disappeared in the body of the patriot hero in whom they had once developed the noblest specimen of that generous love of social life which induced him to devote his existence to his country’s weal; we thought we perceived their influence when those magic charms abandoned the lovely female whose powers had once excited from the philosopher those splendid epithets that ranked her with the other objects of his adoration, celestial truth and god-like genius—which had obtained even from the poet those wonderful strains that at once immortalized him and the object of his song—which had commanded, even in the hero, those glorious devotions which, for far too short a period, illustrated the ever memorable days of chivalry. When those eyes whose soft languor had fascinated every beholder, those cheeks where life had often spread the crimson veil of love—when these were gone, those eyes were dim and sunk, those cheeks were pale, those lips were livid, that bosom depressed, that form rigid and icy cold, when all had thus assumed the darkest and most frightful hues, had gradually lost cohesion and become one mass of horrible putrescence, whose infectious effluvia now threatened destruction almost welcome to those who once adored the animated being—it was scarcely possible to feel all this, and avoid the conclusion that life was a state of force.

It was doubtless this unknown and imaginary power connecting the various phenomena of organic structure that gave origin to the idea of life. But that they are no state of force is proved by this, that while the only notion we have of them is motion—successive attraction and repulsion, electricity, fire &c. exhibit precisely corresponding phenomena, and the last of these was, I believe, on that single account, considered as the symbol of life and intellect by the great Zoroaster.

This and similar facts, I may remark, convince me, that the earth has myriads of times been illumed by the highest attainments of intellect, and as often plunged into darkness. This single point of Indian philosophy was, in my opinion, but the mere shadow of the highest excellence in philosophy in general; and as the greatest cultivation of the human mind, and the greatest misapplication of its faculties, cannot well exist together, I am equally convinced, that the beautiful specimens of art, blended with heterogeneous absurdities, in the monuments of Upper Egypt, afford the most striking proof that, contrary to the common assertion, there were periods in that country when tyrants held no despotic sway over the physical, nor the priests of a false religion over the moral structure of man.

But to return to the subject.—True it is that the affinities of external agents with the molecules of organic bodies are precisely the same during life when their influence is resisted as after death when it operates with the greatest energy; but the power which during life organic bodies possess of resisting the influence of external agents, and even the extension of the sphere of their action beyond the mere bounds of the living body, is, in my opinion, very easily accounted for.

All the particles of matter possess attraction and repulsion, and the largest homogeneous masses, coeteris paribus, evidence them most. Hence, organic bodies, while they possess homogeneity by the subsistence of intimate relations between their parts, evidence attraction and repulsion in the highest degree. While in infancy, these relations are merely forming, the powers of attraction and repulsion are weak; when, in the vigour of life, these relations are most intimate, these powers are greatest; when, in old age, these relations are interrupted, these powers are also diminished; and when, in death, these relations cease to exist between the molecules, or in other words, when the body is no longer organized, the power of combined resistance terminates.

Thus, life is no forced state, but an intrinsic power arising merely from the intimate relation of these molecules, and the greater effects which, in such combinations, they are capable of producing, than when, in death, they have become independent of each other, and their powers disunited, are capable of much less effectual resistance.

Thus, it is, that I would endeavour to shew a connexion between the phenomena of living bodies, and the general laws of nature.

This general and common motion of all the parts, says even Cuvier, forms so peculiarly the essence of life, that the parts which are separated from a living body soon die, because they possess no motion of their own, and only participate in the general motion produced by their union. Thus, according to the beautiful expression of Kant, the mode of existence of each part of inanimate bodies belongs to itself; but, in living bodies, it resides in the whole.

When, I say, that life consists in motion, I make no assertion derogatory to the Deity, for every philosopher is of opinion that motion is to us as mysterious as life; and when I endeavour to trace in its phenomena a correspondence with physical laws, I conceive that I pay the truest homage to a Deity. At all events, it would be dishonest of me to give my sanction to opinions respecting a difference which seems to me not to subsist.

The same causes which terminate motion terminate life. Life begins by motion, and terminates when it ceases; but very curiously it also terminates in consequence of it. In other words, the motion wears out the machine in which it takes place. For, while the functions are most dependent, life encreases; and their very independence, though, to a certain extent, the grand aim of existence, destroys it. The very cause of decay commencing when the different functions have acquired their greatest vigour, arises precisely from their having acquired that vigour, and being, at that moment, most capable of a species of warfare, if I may so term it, with each other, as well, as in some measure, from the greater number of accidents to which a complexity of functions is liable.

That, at this period, the functions may, in a certain sense, be said to combat each other, will be evident to every one who, for a moment, considers that great exercise of the loco-motive functions uniformly interrupts the vital and intellectual, or of the vital functions injures the loco-motive and intellectual, or of the intellectual functions injures the loco-motive and vital.

These powers are always in an inverse relation to each other.

Grimaud seems to have had some idea of this, with regard to the first and second classes of functions. He, says Richerand, has given the most extensive developement to the idea of the constant opposition between those two series of actions, over which preside, according to the opinion of this physician, two powers, which he calls loco-motive and digestive. It is marked in no species of animals more than in the carnivorous, which connect with senses abounding in stratagem, and muscles capable of extraordinary action, an assimilating power of so low a degree, that their aliment, in order to be conveniently digested, must posses a composition analogous to that of their organs.

Thus, the independence which the functions acquire, and the interruptions which their operations present to each other, subjects them to the common laws of impeded motion, and its result, a separation of parts.

When, in manhood, their unison is most complete, life is most vigorous. When, in old age, this unison ceases, life disappears. Hence also, I am convinced, it is, that those animals whose functions are longest dependent on each other, and who remain longest helpless, longest enjoy organic existence.

As motion only can result from motion, so life can only result from life. The vital actions of all animals originate in those of their parents, from whom they are detached precisely when their actions become sufficiently independent of them. I am convinced it is upon this principle, that the egg is detached from the ovary and the fœtus from the uterus, as well as because, in these cases, the ovary and the uterus themselves, after long quiescence, recover an independent action of their own. The same power which enables an organic body to act by itself, forces it to separate from another.

Life then seems, in a great measure, to consist in the successive attraction and repulsion of particles—properties equally common to minerals, vegetables and animals, though in different manners and degrees. Life, however, is not here to be confounded with sensibility, which nevertheless I shall afterwards shew is also possessed by all of them. Life seems inseparable from generation, nutrition and decay, or, in other words, from origin, increase, diminution—a progression which minerals and vegetables pass through as well as animals. Minerals also increase by additions to their external surfaces, vegetables by absorbing from without inward, and animals by absorbing from their internal as well as external surfaces.

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