Confiderations fur les Corps organifes, Où l'on Traite de leur Origine, de leur Développement, de leur Reproduction, &c. & où l'en a raffemblé en Abrégé tout ce que l'Hiftoire Naturelle offre de plus certain et de plus intereffant fur ce Sujet. Par C. Bonnet, des Academies d'Angleterre, de Suede, de l'Inftitut de Bologne, Correfpondant de l'Acad. Royale des Sciences, &c. That is, Confiderations on organised Bodies, their Origin, Developement, Reproduction, &c. Including an Abstract of the moft certain and interefting Difcoveries in this Branch of Natural History. 8vo. 2 vols. Printed for Rey at Amfterdam, 1762.

F all the various arcana of nature, none appear to be fo far removed from the inquifitive and prying eyes of curious mortals, as the generation and propagation of animals and vegetables. The modification of organifed bodies is fo extremely complicated, and the affiftance which anatomical experiments afford us, fo little, that many ages may probably yet elapfe ere we are enabled to form any rational theory of generation. Some ingenious hypothefes, indeed, relating to the animal fyftem, have been lately ftarted by Mr. Maupertuis, Mr. de Buffon, and others; they are all, however, equally liable to so many objections, that we do not find either of them give the general fatisfaction required. It appears to us that our Phyfiologifts all want a leading clue to direct them through the labyrinth, in which they are involved by a multiplicity of myfterious facts. Our fenfes are liable to deception as well as our imagination; and it requires the greatest precifion both of fenfibility and understanding, to profit by phyfical experiments. At present almoft every different phenomenon appears to be confidered as a diftinct myftery; whereas nothing is more probable than that the knowlege of a few leading characters, might enable us to decypher many pages in the book of Nature, which are now totally unintelligible. The misfortune is, that most of our natural philofophers begin at the wrong end of their ftudies; catching the eel of Science by the tail, as the Satyrift expreffes it; fo that it is no wonder if it flips through the fingers. Thus inftead of inveftigating the nature of the fimpleft bodies, fuch as the modification and cohesion of the parts of foffile fubftances, and thence rifing by degrees to the more compound bodies of the vegetable and animal kingdom, they boldly fet out with the nature and properties of the human foul*; defcending from the height of imaginary science where they meet with no obstructions, to

Thus our ingenious Author published fome time ago his Analysis of the Faculties of the Soul. See Review, Vol. XXVII. p 503.

founder

founder at last amidst the fimpleft doubts and difficulties of real knowlege.

Philofophy, fays Mr. Bonnet, having discovered the impoffibility of her giving a mechanical explication of the formation. of organised bodies, hath very luckily imagined that they must have originally exifted in miniature under the form of germes or crganical corpuscles. But may we not afk our Author, by what means, and when, philofophy made the difcovery of this impoffibility? Is the fcience of mechanics carried to its greateft perfection? Or, are even its phyfical principles fo much as known? Who then can take upon them to fay, there is a fingle phenomenon in nature, that will not admit of a mechanical explication? To this we may add, that philofophy hath no bufinefs to form conjectures, which ferve only to remove a difficulty a degree or two back, without obviating it. It is no difgrace to philofophy, to leave things unexplained, which it has not had the means or the time to investigate; but it is highly unphilofophical for men to fupply the want of experiment by conjecture, and fubftitute the vagaries of the imagination for the truths of fcience. When Phyfiologifts have once explained the causes of attraction, of cohefion, of the vis inertia of fofile bodies, and have given a rationale of the laws of motion; it will then be time enough for them to take upon them to fay, whether the formation of organized bodies may, or may not be mechanically explained.

But though we hold the feveral fyftems of generation mentioned by our Author, to be in a great degree vifionary, as we do all immechanical theories in phyfics; yet we cannot deny him the commendations, which are juftly due to his industry and ingenuity; in collecting, and comparing together, the very best of thofe obfervations, both theoretical and experimental, which have been made on this nice and perplexing fubject. Hence, though we cannot recommend this performance as a treatise of philofophy, we efteem it as an excellent and interefting production in natural history. We fhall juft give our Readers, therefore, a general sketch of its contents.

In the first eight chapters, which, we are told, are juvenile productions, and are extracted from a larger work, our Author treats of the pre-existence of the germes of organifed bodies, their growth and nutrition; remarking particularly on the generation of monsters, and the multiplication of the polypus and other infects. He confiders next the microfcopical obfervations that have been made on the femen mafculinum of several animals, and analizes Mr. Buffon's new fyftem of organical moleculæ.

In chapter the ninth, he recapitulates the difcoveries of Mr.

Haller,

Haller, on the formation of chickens in the egg: deducing such confequences from them as ferve to confirm his own theory, and comparing them with the experiments of Harvey; as made ufe of by Mr. Maupertuis, in his Venus Phyfique.

Chapter the tenth contains remarks on the metamorphofes of infects, and the mechanifm of their growth.

In the eleventh, he fhews that the obfervation made on the formation of chickens effectually destroys the above-mentioned fyftem of organical elements.

In the twelfth chapter, we have feveral reflections on the difcovery of the Polypus, with obfervations on the scale of Beings: together with an account of fome uncommon facts relating to vegetables, and the analogy between trees and the bones of animals.

In this part of the work, our Author makes two quotations, from Mr. Formey and Profeffor Koenig; the one tending to fhew that the propagation of infects by dividing them, was known to St. Auguftin, and even fo long ago as the times of Ariftotle; the other intimating that the discovery of the Polypus was foretold by Leibnitz, as a neceflary link in the chain uniting the animal and vegetable creation.

In the fecond volume, the Author goes on to particularife feveral extraordinary facts, regarding the propagation of infects, by flips and grafts; making his obfervations on the reproduction of earth-worms, water-infects, and on the regeneration of the claws of Lobsters. In the third chapter of this volume, he goes out of his way, as a naturalift, to enter into a metaphyfical dif cuffion about the feat of the foul, in the Polypus, and of the divifion of it, by longitudinally dividing the head. The perfonality, or the M, as the French call it, is attached, according to Mr. Bonnet, to the head of this strange Being: but we should have imagined that the Author of the Effai Analytique fur le Facultes de l'Ame, might have reasoned more accurately on such a subject. The difcovery, fays he, of the origin of the Nerves, hath given us fufficient reafon for placing the feat of the foul in the brain. It is not neceflary to fay it refides there in the manner of a body; as it is not a body; but it is present there in the manner of a fimple fubftance. If I am afked to define that prefence; I profefs myfelf to be totally ignorant of the internal nature of the foul, that I know little of it, and that only from fome of its faculties." Now, might we not ask Mr. Bonnet here, whether he is certain that the Polypus hath a nervous fyftem and a brain? and, fuppofing he is, what can he mean by a thing refiding in the brain, yet not as a body, but a fimple fubftance? It is prefent, and yet he does not know what that

prefence

prefence is. How then does he know it is prefent? By its faculties, fays he. But why may not thefe faculties belong to the very brain he is fpeaking of? Why muft he feek an imaginary fubftratum, when there is a real one? Oh! but, fays he, these faculties cannot be the mechanical effect of the modification of the animal. Why not? Mr. Bonnet. That is what remains to be proved. As a naturalift, you had nothing more to do than to attend to the motions and other phenomena of this infect; and if you could not account for them, to leave that task for others; but, to furnish it with a foul, exifting and refiding you know not how, is all metaphyfical trumpery. But to follow our Author a little farther. I fuppofe, therefore, that a foul exifts in the head of a Polypus; and that this foul hath fenfations which it derives from the organs, with which the infect is furnished. I conceive farther that it hath a fentimen: of the prefence of these fenfations; for a foul cannot have any fenfation, without perceiving at the fame time that it hath such senfation. Not that I pretend to fay what this fentiment is; because my foul is not fo made as to feel in the fame manner as that of the Polypus: but I can easily fee, that it is not precifely the fame thing as we call confcioufnefs: Consciousness fuppofing always fome degree of reflection; and we do not attribute reflection to an infect." And yet, we think, he might full as well impute reflection to this infect as furnish it with a foul; unless he will agree to give a foul to every tree and plant likewife. For according to his own fcale, it is next to impoffible to diftinguish between the vegetable that has no foul, and the Polype that hath one; or between the infect that cannot reflect and the animal that can. In fhort, the perfonality even of an human Being is a point too difputable for us, to think of fettling that of a Polypus.

In the fourth and fifth chapters, Mr. Bonnet confiders the vaft diverfity obfervable in the fructification and generation of plants and animals; and in the fixth, makes feveral objections to the conclufions drawn from the microscopical difcoveries of Mr. Needham. The feventh and eighth, which conclude the work, contain farther confiderations on the fecundity and generation of animals, with fome farther ftrictures on the formation and propagation of monsters.

On the whole, the curious Naturalift will find ample matter for inftruction and entertainment, in this performance; almoft every thing that hath been advanced by the best Writers being collected and digested in fuch a manner as to elucidate the fubject in question. He will do well, however, to be cautious of being mifled, by the inferences fometimes drawn from confirmed facts; and above all not to look upon difficulties as re

3

moved,

moved, where only one unintelligible term is fubftituted for another. Thus, our Author tell us, after his favourite physiologist, the celebrated Haller, that "the phyfical caufe of the motion of the heart is its irritability;" and that "the feminal fluid is a fort of stimulant, which irritates the heart of the embrio, and impreffes on it a degree of force, which it could no otherwife receive." But what do we learn by all this? while the mode of irritability, and the action of the ftimulus, are unknown, we are as much in the dark as ever. For, after all, there can be no fatisfactory explication of any phenomenon in nature, that is not mechanically deduced from known and intelligible phyfical principles.

However plaufible and ingenious, therefore, may be the hypothefes of Phyfiologifts in regard to the mystery of generation, they are at belt but mere hypotheses: a number of interefting discoveries remaining first to be made, ere that important fecret is drawn from the bofom of Nature.

Hiftoire du Siecle d' Alexandre, avec quelques Reflexions fur ceux qui l'ont precedé. 12mo, Amfterdam, 1762. Or, The History of the Age of Alexander, with fome Reflections on the preceding Ages.

T is difficult to fay whether Truth fuffers most from our paffion for novelty, or from our prejudices in favour of an tiquity; certain it is, that an Hiftorian runs fome danger from both. A fondness for fingularity may lead him into real, as well as apparent, paradoxes; and an implicit regard to authority, may betray him into the propagation of palpable falfehoods. There is fomething, however, lo becoming a man of genius, in his daring to think for himfelf, that we cannot help applauding the Writer, who lays claim to this privilege, however miftaken he may fometimes happen to be, in deviating from the beaten track of his predeceflors. It is in this point of view, we look upon the ingenious and fprightly Author of the prefent Hiftory; whofe youth might, nevertheless, be held a fufficient plea against much greater objections, than any of those which we could be induced to make against the first eflay of fo agree able and entertaining a Writer.

In his Introduction, he fets out with obferving the too high esteem in which the memory of Conquerors is held, in general; an obfervation which, if not altogether new, is an inftance, a mong many others, of this Writer's juft eftimation of human actions and opinions. "If mankind, fays he, were without

4.

prejudices,