substances in general might no doubt be formed artificially, if we could bring together the elements composing them precisely in the same manner in which they are brought together by the organic process."

Let not our young reader be alarmed at all this, nor suppose that he is unfit to practise physic 'till he understands how those animals are supported who have no nervous system to "take cognizance of each individual particle of blood:" For these he may conclude that the "sua sponte" affinities will be sufficient. Let him, however, be very cautious how he attempts to "bring together elements in the manner they are brought together by the organic process, so as to form organized substances!" For he may be assured, that before he, or this chemico-arithmetical physiologist were born, one and one made a third. What follows will explain this matter better; and the commencement of the succeeding paragraph gives us a fair opportunity of concluding the chemico-physiological part of our Retrospect.

"Thus then, (continues the author,) we consider the vital principle as the immediate cause, not the effect, of the organic process: as a power or principle endued by the Creator, with a faculty little. short of intelligence, by means of which it is enabled to construct such a mechanism from material elements and agents, as to render itself capable of taking further advantage of their properties, and of making them subservient to its use. But it will be doubtless objected, that it is equally difficult to conceive how the vital principle can construct this machinery, as it is to conceive how it can use it when constructed. This must be admitted. It is often as difficult for the chemist to prepare his apparatus, as it is to make his experiments; but the experiments cannot be made without the apparatus. In like manner, one part of an organized being is constructed by

the electric fluid, by means of which we can conceive it to be able, by placing the elementary particles in different states of electricity to separate some, and thus favor the union of others, according to the ends it may have in view. It must, however, be observed, that many organic substances are liable to great and extraordinary changes in external characters at least, without any apparent increase or diminution of their material elements, as, for example, fibrin and albumen,"

the

the agency of another, these again by others, and so on; for no operation can take place without its appropriate machinery. But the original power which appears at present to contrive and regulate these operations, was, as before observed, created by the Deity, and not only gifted with these faculties, but with the additional one also of having its existence in union with material elements and agents, perpetuated by communication from one individual to another, which is the only manner in which organic beings can be produced.

"In these preliminary remarks, the reader, perhaps, will find little new."-In this last remark we perfectly agree with the author.

Thus much in excuse for our inattention to chemistry as connected with physiology. But some greater apology may seem necessary for our apparent inattention to physiological theories founded on no other facts than such as may be traced in a living animal.

Darwin and Brown were both ingenious men, and arrived, as we shall presently see, at the same point by different routs. Another author, we are informed, met Bichât in his road; and we suspect that in this road all other men will meet in perfect harmony. The author refers us to the 520th and following pages of his Treatise on Fever, published anno 1799, for some of his opinions.

"That excitement (says he) which is followed by exhaustion is always healthy. The debility it occasions affects no parts of the system but those on which the animal functions depend, and in them only occasions debility by diminishing their excitability, in consequence of which they cease for some time to be excited, and the animal functions are suspended, that is, sleep takes place; during which, the excitability of the organs concerned in these functions gradually increasing, they become sufficiently sensible to be again roused to action by the usual stimuli. The same stimuli again in a short time impair their excitability, which is again in like manner restored; hence the constant alternation of vigilance and sleep. During neither of these states are the powers of life at all impaired. The system is in as perfect health in a state of exhaustion as in that of moderate excitement. The powers by which the body is preserved do not partake of this alternation; it is confined to those

powers, by which the animal is connected with the external world, by which he perceives and acts.

"The latter set of powers cannot exist independently of the former, but the former may without the latter. We have reason to believe that this is the case in the less perfect animals, which seem to possess no powers but those on which their existence depends; and which may be regarded as the link that connects the more perfect animal with the vegetable world.

"We have ample proof, that, even in the most perfect animals, the vital and natural functions may be in a state of perfect vigour, where the powers on which the animal functions depend never existed. Human and other fœtuses have been born without the head, in other respects well-formed and of the full size. Such a fœtus dies as soon as a ligature is thrown around the umbilical chord, because the blood no longer undergoes that change which is caused by the vicinity of the maternal blood in the placenta, and which is effected, after birth, by respiration; a function, which, depending on the nervous system, cannot be performed by an animal without the brain. Could such a fœtus after birth be made to respire and be supplied with nourishment, we have every reason to believe, from what we know of the animal œconomy, that it would live and increase in size after birth, as it does before it; but it would certainly experience no alternation corresponding to that of vigilance and sleep in the more perfect animal."

Now, if we understand all this, the first part is only the road in which Brown and Darwin met, the one with excitability, the other with sensorial power ;* and each teaches us,

that,

* "Now, as the sensorial power, or spirit of animation, is per petually exhausted by the expenditure of it in fibrous contractions, and is perpetually renewed by the secretion or production of it in the brain and spinal marrow, the quantity of animal strength must be in a perpetual state of fluctuation on this account; and if to this be added the unceasing variation of all the four kinds of stimulus above described, which produce the exertions of the sensorial powers, the ceaseless vicissitude of animal strength becomes easily comprehended.

"If the quantity of sensorial power remains the same, and the quantity of stimulus be lessened, a weakness of the fibrous contractions ensues, which may be denominated debility from defect of

stimulus.

that, when an animal is wearied, he is refreshed by sleep, and may go to work again—that, when he has laboured long in body or mind, he must rest-and, lastly, that he must neither sleep too much nor work too hard. It is true, the author just quoted is to us a little obscure, when he thinks it "necessary to premise, that, by the term exhaustion, he means the state in which the body exists during sleep"-we find our bodies recruited during sleep!

We admit, indeed, that Dr. Wilson and Bichât differ in many points, but suspect that most readers will discover a similarity of language when the former speaks of " powers by which an animal is connected with the external world."

stimulus. If the quantity of stimulus remains the same, and the quantity of sensorial power be lessened, another kind of weakness ensues, which may be termed debility from defect of sensorial power; the former of these is called by Dr. Brown, in his Elements of Medicine, direct debility, and the latter indirect debility. The coincidence of some parts of this work with corresponding deductions in the Brunonian Elementa Medicinæ, a work (with some exceptions) of great- genius, must be considered as confirmations of the truth of the theory, as they were probably arrived at by dif ferent trains of reasoning."-See Darwin's Zoonomia, vol. i. p. 96, 3d edit. 1801.

"Life then, or those functions which we call living, are the effects of certain exciting powers acting on the excitability, or property distinguishing living from dead matter. When these effects, viz. the functions, flow easily, pleasantly and completely, from the action of these powers, they indicate that state which we call health.

"We may, therefore, as we before hinted, distinguish three states of the irritable fibre, or three different degrees of excitability, of which the living body is susceptible.

"1. The state of health which is peculiar to each individual, and which has been called by Haller, and other physiologists, the tone of the fibre. This is produced by a middle degree of stimulus acting upon a middle degree of excitability: and the effect produced by this action, we call excitement.

“2. The state of accumulation, produced by the absence or diminished action of the accustomed stimuli.

"3. The state of exhaustion, produced by the too powerful action of stimuli."-Garden's Lectures on Zoonomia, p. 197.

As

As we have already given our opinion very much at large on the French philosopher,* our readers will not expect us on the present occasion Tantos componere lites!. Few people will question whether secretion and every other property of an animal not controlled by the will, nor always the object of his senses, exist, whether he sleeps or is awake. But there is a difficulty in the language of the English philoso pher which we confess ourselves unable to solve. Which are the imperfect animals that exist" without those powers which connect them with the external world?" How do they procure their food? Probably the author may refer to hydatids and other parasite animals, but this should be explained.

Another objection we make, is to certain inferences on sub. jects which admit of proof. To ascertain how an animal of the class accustomed to have a head can exist without one, it is not necessary to guess whether, under certain circumstances, an acephalous foetus could live and encrease after birth, nor would it be easy to make an experiment on a monster whose deviations in other respects might be uncer tain. Instead of this, we would recommend that an animal should be decapitated, or pithed, that the lungs should be alternately inflated and emptied, and food injected by the œsophagus. Query-How long will such an animal live and grow? Not long, it may be urged; because no heat is excited, and the secretions cease. But may not all this be remedied by Galvanism?

We cannot dismiss this subject without that attention to language, in which we think it our duty never to remit. The writer we have in view seems to consider Bichât's distinction between animal and organic life as synonymous with the nomenclature of animal, vital, and natural functions. To us, the first of Bichât's terms seems applicable to animals only, the second to vegetables in common with animals. But we are at a loss to know how to explain the other three. All functions must be vital, as they only exist during life; and all must be natural, as they exist only by the laws of nature, These three terms, if their order is inverted, appear

* See Lond. Med. and Phys. Journal, vol. kšv. p. 41 and 125.

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