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displayed in the very young animal, in which the peculiar movements of this creature are excitable for a considerable time after decapitation, or the division of the spinal marrow, and long after the cessation of the voluntary and respiratory motions, when it is in a languid and dying state. In the case of the decapitated young hedgehog, after all gasping had ceased, motions of the larynx are still excited on irritating the nostrils, or on irritating the medulla itself; just as the peculiar motions of the trunk are excited on irritating the limbs, tail, or spines, or the spinal marrow."

Dr. Hall corroborates these experiments by a reference to some cases of anencephalous children, which afford the same data for reasoning, with the great advantage of the absence of all mutilation; a circumstance which throws infinite uncertainty over most experiments of this kind on living animals. We hold one anencephalous child to be worth at least a thousand decapitated frogs or dogs. The cases instanced by Dr. Hall have already attracted much and deserved attention from physiologists; we need not therefore detail them here.

Now, on reviewing all these experiments, the first question that suggests itself is, on which of them does Dr. Hall ground his restriction of the reflex function to the medulla oblongata and spinal marrow? The experiments unquestionably shew that the said function does exist in these parts: but where is the proof that it does not exist in the brain?

The only experiments which can be conceived to bear in any degree upon the question are those made on the eyes of the turtle and the frog. Whether it be from these that our author draws his conclusions or not, we cannot tell; but we presume so, because none of the others could even be supposed to have any relation to the matter. We must then remark of the first of these two experiments, that, as the brain and medulla oblongata were both removed at the same time, it cannot prove anything with reference to the brain exclusively; to say nothing of the fact, that the anatomy of the nerves distributed to the appendages of the eye in this class of animals is not sufficiently known to enable us to say with precision, from what source they are derived; and it is evident that the only nerves through which the reflex power of the brain can be brought to the test are those which are known to be cerebral nerves.* The latter objection applies

Thus, if the muscles which close the eyelids be supplied, as the orbicularis in man, by the portio dura, this is a very improper nerve through which to illustrate any function of the brain; since, though it be nominally a cerebral nerve, there is every reason to believe that it is intimately connected, both in its origin and function, with the respiratory nerves; and its function will therefore be necessarily destroyed by the removal of the medulla oblongata.

with equal force to the experiment on the head of the frog; the nerves which supply the eyelids, and the mechanism by which the apparent retraction of the eye is effected, having not hitherto, as far as we know, attracted the particular attention of anatomists. It is to be observed also, that, although the effect of withdrawing the medulla was obvious, the effect of withdrawing the brain, and leaving the medulla in situ, was not tried. If it were only on this ground, therefore, the experiment is inconclusive. But the truth is, that, from the close connexion of the medulla oblongata with the base of the brain, it is nearly impossible to draw any conclusion with regard to the respective functions of these parts from experiments in which one of them is withdrawn. A function which is in reality exercised by the brain may, nevertheless, be annihilated by the removal of the medulla, and vice versa. It is, however, unnecessary to have recourse to experiments of a kind which at best are liable to numerous fallacies, for the solution of a question which daily observation sufficiently elucidates. It is very plain that the reflex function does exist in the brain. When, for example, the pupil contracts in consequence of the impression of light on the retina, we have every condition of the reflex function. An impression made on the optic nerve is reflected along the nerves of the iris to the latter organ, where it occasions a contraction which is independent of the will; and the brain must here be the reflecting centre, because all the nerves concerned in the process are cerebral nerves. The impression of light, also, on the retina of one eye, affects sympathetically the iris of the other, as we often observe in those cases where only one eye is affected with amaurosis. It will not, we presume, be objected to this example, that it is doubtful whether the iris be muscular or not, because this question may now be considered as nearly settled in the affirmative;* and whether it be so or not, does not in reality affect the question of the reflex power exercised by the brain.

If, however, this objection should be made, we will adduce another example, which is free from it, and will answer our purpose as well. It is a familiar fact, that when the supraorbitary nerve is irritated, as by neuralgia, or any other cause, the adjacent muscles are affected with spasms, which spasms cease on the division of the nerve. Now, if this be not an instance of reflex action in the brain, what is it?

Other examples might be adduced, but, as these are less unequivocal, we pass them over. If it be not easy to multi

• Vide Bostock's Physiology, vol. i. p. 182.

ply instances of the reflex power of the brain, it is because comparatively few muscles are supplied by cerebral nerves.

Our author's conclusions with respect to the glottis and the sphincter muscle are evidently premature: analogy may render it not improbable that the action of these parts is influenced by the reflex function of those portions of the nervous mass from which they respectively derive their nerves; but the logical deduction from the experiments is merely that the action of the glottis is dependent on some function of the medulla oblongata, and that of the sphincter on some function of the spinal marrow.

The same remark applies to the conclusion with respect to the panniculus carnosus.

The facts relating to the integrity of the reflex function in the several insulated portions of the nervous mass which fill the spinal canal are new and interesting, and they appear to us to constitute the only discovery contained in this paper. It is to be observed, however, that the inference is hitherto valid only with respect to cold-blooded animals.

The view taken by Dr. Hall of the reflex function as the cause of the tone and equilibrium of the muscles, is ingenious and worthy of attention: still, however, it is only an hypothesis; and we think that the equilibrium of the muscles may be much better explained on the doctrine of the muscular sense. With reference to their tone, one explanation is nearly as good as another, because the very existence of this property is hypothetical.

We have not space to follow our author in the various applications which he makes of the reflex function to the illustration of several morbid phenomena; but, if the reader will refer to them, we think he will consider us justified in affirming, that some of them are hypothetical, and that others have been repeatedly made by former writers, and are indeed generally familiar to pathologists.

In considering the reflex function, especially with reference to disease, it would be interesting to inquire how far it may be exercised by the ganglia of the great sympathetic nerve; but we have not at present time for the investigation, which would also be rendered difficult by our imperfect knowledge of the functions and real connexions of this remarkable nerve. Dr. Copland, in the learned and excellent notes appended to his translation of Richerand's Physiology, divides nervous sympathies into "the reflex, and the direct: the former arising through the instrumentality of the sensorium, the latter taking place independently of it, through the means of the ganglial nerves, and chiefly of those which are

distributed to the blood-vessels, and which form communicating chords between the viscera." (P. 546.) It is possible, however, as hinted above, that one of the uses of the ganglia may be to act as reflecting centres, by which stimuli applied to the extremity of one nerve are propagated to those of others; in which case, the term reflex may be applicable also to the sympathetic actions of the ganglionic system.

In concluding our review of Dr. Hall's paper, we feel ourselves bound to state, that, although it contains some ingenious reasoning, and is well worthy of perusal, [we never read anything of our author's that was not,] its claims to originality appear to us to be exceedingly small.

Elements of Materia Medica and Therapeutics; including the recent Discoveries and Analyses of Medicines. By ANTHONY TODD THOMSON, M.D. Vol. II.-London, 1833. 8vo. pp. 694. DR. A. T.THOMSON is well known to our readers as the author of a Dispensatory which is in everybody's hands, and which unquestionably entitles him to rank as our best writer on the Materia Medica. In the present work (of which only the second volume is before us,) the articles are not arranged alphabetically, as in the Dispensatory, but in classes, whose limits are marked out by their therapeutic power, as the Emetics, the Cathartics, &c. The general mode of action of each class is illustrated by pretty copious remarks; and, moreover, our author has not confined himself so strictly, as in his former work, to the substances enumerated in the three British Pharmacopoeias.

Everything on the Materia Medica which proceeds from Dr. Thomson must have some merit, and our readers will thank us therefore for a notice of the "Elements," confined chiefly to such points as we believe are not touched upon in the "Dispensatory." The following extracts from the chapter on Astringents are not without interest:

"As an astringent, the Sloe was employed in the time of Dioscorides, and is still used as a domestic remedy, although it has been rejected from the Pharmacopoeias. It has one advantage over many other substances in this class of remedies: it exerts no stimulant influence, and therefore may be administered even when inflammatory symptoms exist. It has been recommended in diarrhoas, especially in those of a chronic character, such as are often brought on in India: in hæmorrhages, and as a topical astringent in enlargements of the tonsils and relaxation of the uvula. It was formerly administered as a conserve; but the inspissated juice of the unripe fruit, or a tincture in proof spirit, is preferable. The inspissated hardened juice may be given in powder, in doses of from eight grains to a scruple, three or four times a day." (P. 34.)

"Ruspini's Styptic, one of those medicines which are known by the name of Patent, the preparation of which is kept secret, and which are often little more than frauds of designing knaves on the credulity of the public, owes its powers to gallic acid. Whilst we may declaim against the principle which has withheld the formula from the public, we cannot deny the value of the preparation as a powerful astringent. I have not witnessed its influence as an internal or general astringent; but I have frequently witnessed its power in checking the most obstinate bleedings from leech-bites in children, after all other things had failed. This styptic consists of gallic acid, a small proportion of sulphate of zinc and of opium, dissolved in a mixture of alcohol and rose-water. In proof of this, the same re-agents which affect Ruspini's styptic, affect, in the same manner, a simple solution of gallic acid in alcohol. It yields a brownish-green precipitate with lime-water, which is re-dissolved by an excess of the lime-water, and acquires a reddish hue: and it strikes a beautiful deep blue with the mixed sulphates of iron. As the quantity of sulphate of zinc and of opium is too small to influence the medicine, a simple solution of gallic acid in diluted alcohol will answer all the purposes of this celebrated and expensive styptic." (P. 47.)

We are surprised that our author should have been obliged to have recourse to this styptic frequently in the cases of leech-bites, as the bleeding, if it does not yield to cold water, can almost always be stopped by a minute portion of sponge fastened upon the wound with sticking-plaster.

In administering the acetate of lead, Dr. Thomson insists on the advantage to be derived from giving vinegar at the same time; for the carbonate is the only salt of lead which is directly poisonous, and the vinegar prevents the decomposition of the acetate in the intestines. He also refers to Mr. Laidlaw's experiments, to which we directed the attention of our readers on a former occasion. (Vol. 1. page 120.) We cannot quit the subject of lead without reminding them of the masterly researches of Dr. Christison, detailed in his work on Poisons, page 385 et seq.

The following observations are characterized by the good sense which pervades our author's practice.

"In hæmorrhoids, the propriety of employing astringents depends altogether on the remote causes of the disease. The most common of these is a confined state of bowels; thence purgatives, or rather laxatives, are indicated; when there is heat, hardness, and much pain, leeches should be applied; but after these symptoms are removed, or where they are not present, when the piles are large and the bleeding excessive, then astringents should be employed. pint of cold water thrown into the rectum every morning, by means of a gum elastic bag, an ointment composed of powdered gall nuts, or of kino or catechu and lard, or solutions of the metallic salts,

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