tions exist, the admission of it is so far from being ridiculous, that, without it, the phenomena of animation cannot possibly be explained. Instinctive actions, therefore, are not to be viewed, in the light of anomalous facts, and ascribed to a mysterious principle, uncaused, or to the continued interference of the Deity: they are to be considered, as the result of principles, original in the frame; so that, when the mind is affected, in a certain manner, a certain action, independently of experience, necessarily ensues. In opposition to this opinion, Dr. Darwin asserts, that all our actions, attended with consciousness, are acquired by the repeated efforts of our muscles, under the conduct of our sensations, or desires, or, in the particular language of Zoonomia, that there is no animal action, which is not immediately irritative, sensitive, voluntary, or associate. This point, therefore, is decisive of the question. If it be proved, that there exist fibrous motions, which have not been acquired by the repeated efforts of our muscles, or which have not originally been excited by irritation, Dr. Darwin, however unwilling to consider an animal, as "little better than a machine," must have recourse to that instinct, which he characterizes, as inexplicable, but which is, in truth, inexplicable, only as being an ultimate fact, in animation, and not more mysterious than the mode, in which sensation is induced by irritation, or volition by sensation. In his definition of actions, as opposed to instinct, Dr. Darwin has himself admitted its existence. They are "acquired by the repeated efforts of our muscles, under the conduct of our sensations or desires." By advancing a few steps from the difficulty, he has thought, that it was completely obviated. The phenomenon, to be explained, without recourse to instinct, is not the repeated effort of the muscles, but their primary action. Of this sensation is the remote cause; and the only mode, in which the muscular contraction can be explained, is by supposing a necessary connection of the particular motive of affection with the particular sensation. In these circumstances, no muscular action can be justly said to be acquired. Thus, to use one of the instances, adduced by Dr. Darwin, the fœtus cannot "learn to swallow by a few efforts:" for the volition, which excites the muscles of deglutition, will either be primarily induced by the sensation, or, if similar effects result from similar causes, will not be induced at all. The action, therefore, is not acquired by the repeated efforts of our muscles, but is original; or, in other words, when the mind is affected, in a certain manner, by the stimulus of food, the action of the muscles of deglutition necessarily ensues. The contraction is the effect of an essential principle of life; and experience, instead of adding to the stock of volitions, can do nothing more, than repeat the primary contractions. To consider repetition, or experience, as the cause of any muscular motion, implies a contradiction: for experience presupposes the motion, and the effect must thus have existed, before its cause. When sensation has frequently succeeded the motion of a fibre, it is said, in its turn, to excite the motion. But, admitting this mutual convertibility, the sensation can have no influence on any other, than that particular fibre; and, in the original motion of the muscles of deglutition, the excited excited fibres are different. Sensation, indeed, precedes their motion; but there is no greater reason, that an affection of the sense of taste should be followed by an affection of the muscles of deglutition, than of any other muscles of the system. The principles of Zoonomia do not explain the connection; and it can only be traced to the original constitution of the mind, by which it is predisposed to exert itself, in producing a certain motion, in consequence of having been affected, in a certain manner. Instinct is the term, that denotes this predisposition; and we are thus obliged to recur to an * occult quality, to an inexplicable something, which connects with sensations, actions that have no apparent bond of union.' The curious instances of animal sagacity, recited in the Zoonomia, are examined on this principle; and their dependence on it is pointed out with the author's usual acuteness. We apprehend, however, that there is more apparent than real difference between his sentiments and those of Dr. D. on this subject. Both agree in referring the actions of animals, in the disputed cases, to a process of thought; similar, in its nature, but inferior in its extent, to that of the human intellect. The present author, indeed, intimates a peculiar opinion, in the note to p. 288; yet he seems to admit that the difference of instinct arises merely from the different effects of organic structure. I do not contend, that the vital principle is really the same, in the different tribes of animals, but that its sameness, in opposition to his own conclusion, is a necessary consequence of Dr. Darwin's theory. In allowing peculiar instincts, I suppose an original difference of the vital principle; though it is, perhaps, not too bold a supposition, to consider the instincts of the different tribes of animals, as the same: that is to say, they are all predisposed to act, in the same manner, when the same sensations exist; but different sensations, and, consequently, different actions, are excited by the same external objects, from the different structure of the organs, which are the medium of sensation.' Dr. Darwin's theory of the origin of our ideas of Beauty, and of Love, is next considered. As Mr. B's objections cannot be condensed into smaller compass than they occupy in his own book, we must content ourselves with observing that they are at least highly ingenious, if not entirely conclusive. The origin of the Signs of our Emotions is discussed in a similar manner. *I do not use the term, as peculiar to instinct for the nature of every quality is, in truth, occult. We know, that agreeable food induces the action of swallowing, and that the magnet attracts iron; but, a priori, we might, with equal reason, suppose, that the iron would be repelled, and the sensation followed by the motion of my arm.' In treating of the Catenation of Motions, Mr. Brown, still dwelling on the original imperfection in Dr. D.'s theory of sensorial power, asserts that all the associate actions, of which the Doctor had already treated, are catenations of animal mo❤ tions; and that the present section is either superfluous, or improperly placed; for, if new laws of association be inferred, this should have formed a part of the preceding sections on that power. For the proofs and illustrations of this opinion, we must desire our readers to consult the book.-Perhaps in this, as in other instances, the effect of Mr. Brown's reasoning will be rather to strengthen our impression of the difficulty of the subject, than to furnish satisfactory conclusions. We feel our obligation to the hardy adventurer who dissolves a fairy edifice into its original elements: but his merit is incomplete, if he does not place us again on firm ground. In the section on Sleep, Mr. B. combats Dr. D.'s theory on account of its inconsistency with the fundamental principles of the Zoonomia. He has introduced one remark which is applicable to the fashionable style of theorizing, and which, on that account, deserves the notice of our readers: • Dr. Darwin has been deceived, by thinking, that he explained sleep, when he only stated its phenomena. Sleep, it may be granted, consists in the suspension of volition; but he will gain nothing from the admission; for the suspension is itself the phenomenon, to be reconciled with his theory. P. 346. When we have laboured through a heavy recital of facts, masked in ambiguous language, which an author has imposed on the public as a theory of the very facts recited, we have sometimes thought of our old friend Swift's method of explaining a difficult subject. He, in mercy to his readers, presented them only with an hiatus, uncommonly wide, and added, now this I take to be a clear and full account of the matter. The application of Dr. Darwin's general principles, to refute his particular doctrines, is on this subject as dexterously managed by Mr. Brown as on other occasions: yet the frequent repetition of this operation, in the course of so large a volume, becomes at length fatiguing, and the reader is ultimately rather overwhelmed than convinced. In his observations on the doctrine of Vertigo, Mr. B. has introduced some interesting remarks concerning ocular spectra, He supposes that the apparent motions of objects arise from a deception of the imagination, by which we consider ourselves as still in motion, after we have ceased to revolve. In this instance, we may perhaps retort on him the accusation of merely stating the fact, instead of accounting for it. In the section on Drunkenness, Dr. Darwin is again made to oppose himself. The arguments on the subject of the Propensity to Motion are too long for insertion, and do not admit of abridgment. We shall extract the author's remarks on imitative motions, as they relate to a pathological doctrine of high importance, which has been too often treated in the loose manner to which Mr. Brown objects: • The production of matter, by the membranes of the fauces, in syphilis, and of infectious saliva, by the salivary glands, in hydrophobia, is ascribed to imitation of the motions of other parts of the system. Yet no reason is assigned, that the imitation should take place, in these parts alone. The irritative sympathy must have power, in every part, or in none, unless particular coexistence, or succession, bave given rise to particular associations. But, in these cases, no original coexistence, nor immediate succession of motions, can be traced; and, therefore, the partial sympathy is not referable to any of the laws of Zoonomia. • In inoculated small pox, the original matter is supposed by Dr. Darwin to be diffused, through the blood; and the production of similar matter is thus explained. "These particles of contagious matter stimulate the extremities of the fine arteries of the skin, and cause them to imitate some properties of those particles of contagious matter, so as to produce a thousand fold of a similar material." This explanation is not merely hypothetical, in the highest degree, but wholly unintelligible. If the matter of the fibres be different, it is impossible for it to become similar to the contagious matter, in any of its qualities. To imitate is to act, and contraction is the only mode, in which the fibres can act; but no degree of contraction can resemble a state of matter, which is wholly unsusceptible of contraction. On Dr. Darwin's hypothesis, the arterial motion is unnecessary for, if the arteries do not exist, in the same state, as the contagious material, no imitation has taken place; and, if they exist, the same state, the contagious material, without their assistance, would have produced new matter.' The supply of new particles, in the process of nutrition, is referred by Dr. D. to the animal appetency of the glands, and of the absorbent system. To this opinion, our author objects; because it supposes those parts to be endued with sensation, which Dr. Darwin had denied them to possess. To us, indeed, this particular doctrine of the Zoonomia appears only to multiply difficulties: since it ascribes to every minute gland, or lacteal vessel, the properties of a perfect animal, without advancing one step towards an explanation of those properties. Mr. B.'s arguments against the supposition, that the earth was rather generated than created, p. 343, in the section on Generation, will hardly be thought conclusive, even by those who differ on this point from the notions of Dr. Darwin. The * The objections to the supply of blood, and consequently, (according to the Zoonomia,) of oxygen, to the foetus, are likewise inconclusive. On this hypothesis, (says Mr. B.) much must be done, in the short space of a few hours. New blood vessels are formed into a complete circulatory system: they are drawn to the sides of the uterus: and the motions of the fluid in which they float, cannot prevent them from adhering to the vessels of the parent.' If Mr. Brown will refer to the tables of Dr. Hunter, or of Dr. Denman, he will find that much of what he has here stated as an hypothesis is matter of ocular demonstration.-Ile has objected, with more success, to the formation of a perfect foetus from a simple living filament:-but, indeed, most readers will probably think that he has bestowed unnecessary pains on the examination of an opinion which is confessedly gratuitous. His remarks on the still bolder hypothesis advanced in the Zoonomia, which derives all living bodies from a similar source, we shall give in his own words: The various species of animal, and vegetable life, Dr. Darwin believes to have proceeded, from a single living filament, susceptible of modification, by the accretion of parts, and by its own exertions. This opinion may, perhaps, surprise us into momentary assent, by its boldness, and the wonderful simplicity, which it seems to in troduce; but, if we demand evidence, we obtain only a few loose analogies, which do not favour the supposition. Degrees of qualities, as of strength, and swiftness, in the horse, may, as Dr. Darwin contends, be in some measure hereditary; but no new quality is su perinduced, and, therefore, the species continues the same. The winged butterfly, it will also be granted, bears little resemblance to the creeping caterpillar, or the respiring frog to the subnatant tadpole; but the wings, and the lungs are not communicated to their posterity. The butterfly, and the frog produce again the caterpillar, and the tadpole; and thus, instead of continued improvement, a circle of changes takes place. The supposed original filament must have required nutriment, for its growth: yet no animal, nor vegetable matter, was in existence; so that, instead of giving rise to the various system of life, it must have perished, or continued to exist, unexpanded, and alone. But,, admitting it to have been capable of growth, and reproduction, as sexual generation was impossible, in a single individual, it could multiply itself, only by the accretion of parts. Such a progeny, it is observed, are always exact resemblances of their parent," p. 523. To what, then, if we suppose a single original filament, is the present difference of sex, and of species, to be ascribed? Dr. Darwin seems to consider the animals of former times, as possessing powers, much superior to those of their posterity. They Should not this word be exchanged for circulating? Circulatory, if admitted in English, must refer to quackery. Rev. reasoned |