LIFE.

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the knowledge of things becoming and honorable," says Aristotle, quoted by Barclay, "be held deservedly in high estimation, and if there be any species of knowledge more exquisite than another, either on account of its accuracy, or of the objects to which it relates being more excellent or more wonderful, we should not hesitate to pronounce the history of the Animating Principle justly entitled to hold the first rank."

The belief in the existence of a definite "principle of life" thus announced, was, in some form or other, universal among the ancient philosophers. Whether material, ethereal, or spiritual, it was assumed as a necessary fact. Indeed, it continued to interweave itself so completely with the current opinions of succeeding ages, that when Lawrence, the popular lecturer of the London Col

lege, first denied it, he was denounced as an infidel and an atheist, and his work laid under absolute, though indirect sentence of outlawry. But now his views are apparently in the ascendant, and we shall find a large proportion among the more recent authorities in full accordance with him; by some of whom, indeed, his "prohibited" book is mercilessly plundered without a syllable of acknowledgment.

What, then, is life! regarded as a condition mysterious, incomprehensible; a power undefined, apart from all others; at once capable of indomitable opposition to all, and yet liable to be utterly repressed or crushed by slight contingencies; a force, and the manifestation of that force; a creative or constructive principle, and yet the creature or result of agencies and formative circumstances; a mere series of movements and actions, connected and dependent?

We speak of the dynamic changes of disease as flowing directly from the abnormally-exerted energies of the vital force, but without clearly comprehending what is this vital force, and how it differs from such other forces as are known to the natural philosopher. All extremes of opinion upon this subject have been held; but the great majority of physiologists at the present day are ready to subscribe the doctrine maintained by the profound and ingenious Matteucci, that, while living beings are "endowed with the general properties of all natural bodies," and, therefore, amenable to all known natural laws, yet

the phenomena which they offer to our observation "are not all explicable by reference to physical and chemical forces merely." In all life there is something peculiar which modifies the action of these forces.

In the present state of our knowledge, this is, indeed, the only tenable position intermediate between those who, on the one hand, ascribe all vital changes to mechanical and chemical influences, and, on the other, those who deny the compatibility of impulses which they represent as being in absolute contrast and contradiction.

The phrases "principle of life" and "vital principle" are in familiar usage in all our discussions, but, as Mayo has well remarked, "this term principle has been generally employed as the letters of the alphabet are by algebraists, to denote an unknown element, which, when thus expressed, is more conveniently analyzed;" or, as I should prefer to say, more conveniently examined in its several relations. It is curious to see how it is regarded by the numerous theorists who have successively endeavored to philosophize concerning it.

Willis attributes all living actions to the "callidum innatum," as he denominates it, "a material element of an igneous nature," and fortifies his opinion by adducing in its favor some of the highest names of antiquity— Hippocrates, Democritus, Epicurus, and Pythagoras.

Scaliger and Fernel have imagined a superior "callidum innatum" as the principle of life; not the material igneous element of Willis, but a "more divine heat, spiritual,

aerial, ethereal, or composed of something elementary or ethereal." Harvey, the discoverer of the circulation, bluntly maintains that "the blood is the animating principle, or the substance of which the anima, or life, is only the act." John Hunter, that eminent example of "patient labor," after examining this subject, as was his wont, with the most pains-taking and persevering attention, arrives at the conclusion that "there is a principle of life connected with all the parts of a living body, solid as well as fluid; a materia vitæ diffusa." Abernethy accepts and endorses this view. "My mind," he says, "rests at peace in thinking on the subject of life as Mr. Hunter has taught;" but he dwells with no little emphasis on what he calls the correspondence between "the phenomena of electricity and of life," a hint caught up and wrought out at much length by Wilson Phillip, and recently carried through the analogies of galvanism and magnetism, and pored over in the most mysterious and significant way by the mesmerists.

Cuvier tells us that "life consists in the sum total of the functions;" and Bichat, a little more explicitly, affirms it to be "l'ensemble des fonctions qui resistent à la mort." In this latter spirit, an ancient writer points it out as "illud-putredine contrarium;" and Carlyle, speaking ironically of "some small soul," has the same idea, "it saves salt."

Coleridge, one of the profoundest thinkers of the age, capable of the fullest consideration of this obscure topic

in every point of view, physically as well as metaphysically, zoologically as well as philosophically, sums up the results of his inquiry in a truly transcendental form. "My hypothesis will, therefore," he says, "be thus expressed that the constituent forces of life in the human body are, first, the power of length, or reproduction; second, the power of surface (that is, length or breadth), or irritability; third, the power of depth, or sensibility. With this observation, I may conclude these remarks, only reminding the reader that life itself is neither of these separately, but the copula of all three; that life, as life, supposes a positive or universal principle in nature, with a negative principle in every particular animal; the latter, or limitive power, constantly acting to individualize, and, as it were, figure the former. Thus, then, life itself is not a thing, a self-subsistent hypostasis, but an act and a process."

Here we are left at the end, as the reader will notice, entirely without any reference to the agent performing the act, or the motive power which determines it, or carries on the process. This is the point at which we will perceive the deficiency of all those theories which prefer to place life before us merely as an effect, or concatenation of effects; the absolute necessity of a first-moving agent, capable of generating action, a cause adequate to the production of the alleged effects, seeming to escape the mind during the discussion.

Carpenter, who, of all English physiologists, is most