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On this subject we find, indeed, that few original opinions or arguments have been advanced on any one point since the days of Lucretius, and even of Aristotle. The novelties which have been since introduced, are found to be chiefly novelties of expression, not of ideas: accompanied, it is true, with certain characteristics of manner, and also with attempts at additional illustration from the views of the microscope, and the visions of some pretenders to chemistry; The impelling motives, however, the leading opiņions, and the leading arguments, as our author justly observes, have undergone scarcely any change, and appear at this day to be generically and specifically the same that they were several centuries ago.

The object of the learned and most laborious work now before us is to give the history of opinion, on “Life and Organization," from the first dawn of philosophy down to our own times-from Democritus and Ocellus Lucanus to Lawrence and Abernethy. It is accordingly to be regarded as an outline or compendium of every thing which has been written on this interesting subject ; and the reader, we assure him, will find it replete with information, and even with entertainment; distinguished too by a very acute logic in exposing the absurdities of even the most celebrated physiologists ; supporting every where the cause of religion and morality against a host of insidious or infidel authors; and at length we must own ending, like all other books on the same topic, by an implied acknowledgment that life, or the vital principle, or whatever else the thinking, conscious part, in man shall be called, will for ever elude the researches of the most ingenious and accomplished inquirers.

Of the Greek philosophers, and their fantastic reveries, 'it would be absurd to speak at any length ; for it somehow strikes us that we have got only the verbal expressions used by those clever persons, without possessing a key to the precise meaning of either their arguments or their terms. This opinion is forced upon us by the simple consideration that their language, taken in its ordinary acceptation, is either unintelligible or positively absurd. What, for example, could be meant by asserting, as the Stoics were pleased io assert, that the human soul was air, warm and ignited, or as Hippo maintained, that it was water ; or, as Democritus taught, that it was fire ; or finally, as Heraclitus dreamed, that, as the soul of the universe was a vapour, or exbalation, from the moist elements, so the souls of animals were vapours, or exhalations from their own bodies. Thales was the first who held that the soul was always in motion, and itself the

origin of that motion. Pythagoras, again, was pleased to teach in the language of allegory that it was a self-moving inorad or unit; Plato maintained that it was a substance conceivable only by the understanding, and moving according to harmony and number : Aristotle imagined it to be the first entelecheia, or (as George Wither expressed the idea) “ the first continuall motion of a bodie-naturall, having in it those instrumental part3, wherein was possibility of life;" and Dinarchus (or Dicoearchus, as others will have it,) de. fined the soul to be a “ harmony of heat, cold, moisture, and dryness."

The total want of meaning in these expressions really induces us to believe that we have lost the key to the proper import of the language employed by the ancient Greek philosophers. In opposition to this hypothesis, bowever, it may be alleged that the writings of modern physiologists, on the . subject of Life and Organization, are not a whit more intelligible: and that the ravings of Democritus, in regard to cogi. tative atoms, and of Heraclitus, in reference to an intellectaal vapour, may be fairly matched by the extravagancies of Robinet, the absurdities of Maupertuis, and even by the childish fictions of several of our own countrymen. In truth, between those who speculated two thousand years ago, and the authors whose works are still recent from the press ; the main difference consists in the physical illustrations employed by them, whilst endeavouring to recommend doctrines which, in either case, have had no other foundation than the wildest hypothesis, or the most unwarrantable assumptions. The more ancient and the more modern physiologists have respectively availed themselves of the lights of science, according to ihe actual degree of advancement to which it had attained ; and they have incorporated their speculations with the notions prevailing at the period when they wrote, relative to the properties of material substances, and thus we have, in the works of the former, a constant reference to atoms, to motion, or to number, whilst in the publications of the latter, we have substituted in their place the equally obscure expressions of chemical affinities, electrical energies, and magnetic attractions ;-all obviously unsuitable to the nature of tbe inquiry in which they are employed.

All the opinions hitherto entertained respecting the vital plienomenon, says Dr. Barclay, "may be ascribed to one or other of two causes ; namely, to a certain organism of the materials of which the visible structure is composed, or to a principle totally distinct from that structure, recognized by all mankind, as something diferent from body, and is

" An egg,

vested with a distinct appellation in all known languages. Those who refer life to a particular mechanism, may be supposed to reason as follows.

when recent, does not exbibit, and could never have exbibited any thing analogous to vital phenomena. The eye cannot trace in it any thing more than an organized structure, and yet in that state regulate the temperature so as to prevent the derangement of its parts, and it will continue not only for weeks, but for months and years, a collection of mere organized matter. Yet after these years apply the degree or quantity of heat that the parent communicates when she is hatching ; imitate her instincts, turn it at times to continue the heat with occasional interruptions, and the embryo within will begin to grow, to move, and to live, and at last will exhibit all the instincts, appetites, and passions belonging to the species which first gave it birth. Suppose that this is a species of swallow, or one of that kind that may be reduced to the torpid state ; suppose again, that upon the approach of the cold season, the temperature of this bird, artificially hatched, becomes low, its digestion languid, and that all its functions shall in succession be gradually suspended ; it must again, as it was in the egg, be reduced to a mere organized structure; and yet this structure, as well as the egg, will upon

the return of warmth and of plenty, begin not only to move and to live, but to seek for a mate, to propagate its. kind, and display all the instincts and passions, and the restless vivacity peculiar to its tribe.

“ In this case do not the several phenomena of life proceed entirely from organism and heat? If, besides these, there be any other cause, of which of the senses it may fairly be asked, is it the object? Who is the man that bas seen it or heard it? Who has touched it, tasted it, or smelled it? We need only look around to be fully convinced that, besides these two, any other cause is merely imaginary. Do we not observe most of our insects and plants gradually sinking into motionless torpor as the sun is retiring in the season of autumn? And observe we not again, these insects and plants in full animation, as he returns with exhilarating rays in the season of spring? And while we see this with our own eyes, do we not hear from voyagers and travellers that, between the tropics, where he constantly dispenses so liberal a portion of his animating influence, the insects live, and the plants are adorned with blossoms, and fruits, and with verdant foliage all the year round? If this hypothesis can sufficiently account for the vital phenomena, what kind of unnatural perverseness can possibly induce us to grope in dark and hidden corners in search of invisible imaginary beings, to perform what is naturally, obviously, and demonstrably performed without them ? After seeing so clearly what we bave seen, we remain content with the obvious causes, and shall leave enthusiasts to hunt after mysteries, or indulge in fanciful whims and hypotheses, as being perhaps more congenial to their taste than facts and observations."

In this way does our author personate the materialist, and bring forward the reasonings usually employed by that class of inquirers, in the department of physiology. The chief objection, as is well observed, to the hypothesis on which the whole argument turns, arises from the undeniable fact that organic structure (or organism, as the Doctor calls it,) is itself an effect—and an effect, too, produced by vital functions and cannot therefore, in accordance with the rules of strict philosophy, be regarded as the cause whence itself bas arisen. As the seeds of plants and the eggs of animals are evidently as much organized structures, and as much the effects of vital phenomena, as the plants and animals from which they spring, those writers sport a very silly and puerile sophism, who first represent them as extremely minute chemical particles, and then, by taking advantage of their organism, say that by means of their chemical affinities, they afterwards produce animals and plants. The fact is, they are the animals and plants themselves, in their early or incipient state of existence: and this sophism, continues our author, instead of accounting for their structure and organism, does when closely investigated, imply no more than that plants and ani. mals, however young and however diminutive at their commencement, grow older by time, and larger by nutrition.

It is indeed extremely dislicult to draw the line between the causes of vital phenomena and the conditions necessary to the existence of life; whilst it is obvious that from confounding and viewing as one these two classes of circumstances, the principal errors of physiology have arisen. For instance, corn may be preserved, when properly securest from the approach of air and moisture, several hundred years, during which long period the vital principle remains in a torpid state, retaining only what may be called the potentiality of life, and yet, at the end of it, if the grain be deposited in soil suitably prepared, the long-suspended functions of vitality will begin to manifest themselves, and the embryo plants to expand their several members in healthy vegetation. Now, as in this case the physical causes or conditions of life were heat and moisture, we may perhaps discover the grounds upon wbich the ancient philosophers pronounced life (tuxen) to be in some instances fire, in others water, and in most cases a combination of these two elements. It sounds ex. cessively absurd to say that the soul is heat, or air, or moisture, or motion; but if we regard these in the light of conditions essential to the developement of the vital energies in an animal or a plant, the language of Grecian philosophy becomes at least somewhat intelligible.

The first chapter of Dr. Barclay's Inquiry, wbich gives a

summary view of different opinions entertained by the ancients concerniug the cause of the vital phenomena,” is extremely amusing, and contains within a comparatively small compass, the result of much reading and much more reflection. It may strike some readers perhaps, that there was no necessity for so many extracts from Lucretius, or so minute a commentary on the epicurean notions, which he has immortalized in his celebrated poem, or finally so full an exposition of the "origin of things,” and the " order of things,” according to the fancies of the several atbeistical scribblers whose opinions are preserved by Diogenes Laertius. To us, however, this is the pleasantest part of the book. We have temper sufficient to trifle with the luxuriant imaginations of ancient sophists, who knew little of physics, and nothing of true religion ; but we can exercise no forbearance towards the sceptical writers of a Christian country, who abuse the knowledge which the others ardently sought, and voluntarily run into the darkness from which their predecessors laboured to escape.

The third chapter of the work introduces us to the “ opinions of those who since the revival of learning in Europe, have treated of the causes of organization, and ascribed the principal phenomena of life to crganic structure.” The writers of this order, among whom are ranked Leibnitz, Haller, Buffon, Blumenbach, Gassendi, Cuvier, and Cabanis, are divided chiefly in regard to the inquiry which respects the existence of the soul before it be united to a human body; and they take their place on either side of the question, according as they stand for involution, or for dissemination. It is imagined by both that the souls of men have had a sort of being since the first creation of things; that “ all the generations of plants and animals which are yet to appear, have been existing somewhere or other for thousands of years; and that embryo animals, so long invisible, make their first appearance in the sperm of the male, as seminal animalcula; or under the appellation of germs, if they appear in the ovarius of a female.” It seems to be with respect to the mode in which these infinitesmal organisms are preserved

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