ance. Certainly all ribald jests should be avoided, as well as all prudery; an honest, manly, business-like firmness should be the rule of conduct: going straight to the object with few words, unless reproof be necessary. When we remember how extensive the relations of the sexual functions are, and how imperious the instinct, and the more imperious when the man is the most inexperienced, there must be a large mass of human suffering that the prudish practitioner never has the opportunity to alieviate. We believe the venereal and obscene quacks gather the richest harvest of any mediciners.

An interesting question arises in considering how far experiments in medication may be carried. M. Simon thinks only the few who are properly qualified by opportunities, previous studies, and experience, should undertake the difficult duty of filling up the chasms in therapeutics. Experimentation is unjustifiable (except in incurable cases) by the ordinary practitioner. He must be content to follow, and not aspire to lead. M. Simon seems to object strongly to the use of arsenical preparations. He would have their use absolutely forbidden. In this point we differ much from M. Simon. Given with due care and attention, much good may be done by them.

We pass rapidly over the remainder of the volume. A chapter on the use of intimidation in treatment and prophylaxis is followed by another on euthanasia, and the treatment of the dying; and this ends the second division of M. Simon's subject. The third division considers the duties of practitioners towards society. The fourth is occupied with the rights of the profession, and comprises medical organization, and civic status, privileges, immunities, and rewards. As the questions discussed belong to hygiene and medical polity, and are thus only incidentally a branch of medical ethics, we will here hold our pen. In conclusion, we may honestly say of M. Simon, as Sir Kenelm Digby observes in his critique of Sir Thomas Brown, "His wishes and aims, and what he pointeth out, speak him owner of a noble and generous heart."

ART. X.

The Descriptive and Physiological Anatomy of the Brain, Spinal Cord, and Ganglions, and of their Coverings. Adapted to the Use of Students. By ROBERT BENTLEY TODD, M.D., F.R.S., Professor of Physiology in King's College, London, &c.—London, 1845. Small 8vo, pp. 284. With 38 wood-engravings.

THIS little work is a reprint of the article "Nervous centres," in the 'Cyclopædia of Anatomy and Physiology,' with several additions, and some alterations, suggested by its reperusal as it again passed through the press. It owes its appearance, as a separate volume, to the frequent complaints which have reached the author, from students and others, of the want of a description of the Brain and Spinal Cord, embodying the most recent observations on the anatomy of these important organs. These complaints we regard as well-founded, but we are not quite sure that the present reprint is the means best fitted to allay them. We are

confident that there is no part of the human body, which so fully needs all the illustration and aid to be derived from comparative anatomy, as the nervous system requires; and we are sorry, therefore, that any treatise, expressly devoted to it, should exclude the valuable information afforded by the researches, that have been recently made upon other types of structure. As an exposition of the structure of the nervous centres in Man, however, we are disposed to regard it as the most full and accurate that has yet appeared in this country, and to recommend it to the attention of the student accordingly.

Prefixed to the anatomical details, which constitute the bulk of the volume, is a series of "Aphorisms respecting the nervous system," which presents, in a very clear and concise form, the chief truths which have been ascertained in regard to its functions. We must take exception, however, to the language in which some of them are couched, as tending to mislead the reader; though we cannot believe that Dr. Todd's ideas on the subject are really different from our own. "The nervous force,"

he justly observes, "is a polar force, resembling electricity in the instantaneousness of its development, and in the rapidity of its propagation, but differing from it in several important features. It is a peculiar feature of the nervous force, not only that it may be developed under the influence either of a mental or of a physical stimulus, but that, being excited by a physical stimulus, it is capable of affecting the mind." So far, so good. The nervous force itself is recognized as the same, whether excited by the will acting through the brain, or by an irritation applied to the trunk of the nerve; and this is in accordance with sound philosophy, which forbids us to regard as different the conditions into which the nerve is thrown by these two agencies, the sole manifestations of those conditions, exhibited through the muscles, being precisely the same. But, continues Dr. Todd:

"14. Hence nervous actions may be conveniently distinguished into two classes, according as the mind participates in them or not; namely, mental and physical.

15. Mental nervous actions are those which originate in, and are excited by, an act of the mind, as all voluntary actions; or which, originating in a physical impression, produce an affection of the mind, as in all sensations.

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Of

16. Physical nervous actions are those which take place without the necessary intervention of the mind, and which result from a physical exciting cause. this kind are all those actions which are caused by a physical change, frequently morbid, in a centre or in a nerve, and those which result from the excitation of the vesicular matter in which a motor nerve is implanted, by the stimulation of the peripheral fibres of a contiguous sensitive nerve. These latter have been designated reflex actions; and although most of them, in health, are attended with consciousness, still this mental state is in no way necessary to the perfection of the nervous act, and should be regarded rather as an incidental accompaniment to it, than as an essential part of it." (p. xii.)

Now we cannot but regard the terms "mental nervous actions," and "physical nervous actions," as utterly meaningless, or as involving ideas altogether incongruous. If it be admitted that the "polar" condition of the nervous system itself is the same, whether it be excited by a mental or a physical cause, where is the distinction between the actions which are the manifestation of that condition? Should we say of the fall of a

stone to the earth, that it was a case of "mental gravitation," if it were let go by an act of human will, but of "physical gravitation," if it were thrown down by the wind, or detached by a stroke of lightning? The idea that the "polar" condition of the nervous system is itself different, according as, in the one class of changes, it is destined to produce sensations or to excite reflex actions, or as, in the other class, it originates in the will or is produced by a physical cause,-appears to us quite unsupported by evidence; and we are satisfied, from the previous aphorisms, that Dr. Todd has no intention of propounding it. What, then, can be the meaning of the terms "mental nervous," and "physical nervous?" The nervous action is one thing, the mental action another. The nervous action is always physical; that is, it is comparable in its nature (so far as this is known to us), and in the conditions on which this is dependent, with other physical actions. Of the nature of mental action we know nothing, it is completely unlike everything else, "none but itself can be its parallel." But we know that it is connected, in some way that we cannot comprehend, with the proper physical actions of the nervous system; being stimulated by the latter, when the part that is in action is the one that has the power of exciting sensations in the mind; and in its turn being the stimulus of the latter, when the will, or an emotional or instinctive impulse, is directed to the production of muscular movement. Thus, then, nervous action, itself physical, may be produced or stimulated by physical causes, or by mental causes; and it may be productive of physical or of mental changes, according to the part of the nervous system concerned. But such a difference in the causes or in the effects of the action does not warrant the combination of terms employed by Dr. Todd; the only excuse for which would be looked for in a difference in the action itself, which is not admitted by Dr. Todd any more than by ourselves.

We shall make a few quotations from the anatomical portion of the work, which may give an idea of the clearness and amplitude of its descriptions. After entering at some length into an account of the craniospinal fluid, to which particular attention has been drawn by Magendie, Dr. Todd thus continues:

In

Practical men are too much in the habit of attributing morbid phenomena of the nervous system to the influence of the pressure of a liquid effusion upon the brain or spinal cord. Many facts tend to show, that, in a large proportion of cases, especially in the adult, the occurrence of an increased quantity of fluid, either around those centres or within the ventricles, is a result, and that it is probably a result of a conservative kind, consequent upon a morbid change which depresses the general nutrition of those organs themselves. We have seen how the universal decay of the tissues, which characterizes old age, favours the increase of the cranio spinal liquid, when it affects the brain and spinal cord. examining the bodies of habitual drunkards, patients who die of delirium tremens, or of cirrhosis of the liver, the quantity of fluid is always found to be considerable, and the brain shrunk. In bed-ridden persons, who have ceased to exercise their faculties for some time, whether for mental or bodily exertion, the same phenomena are witnessed. When there has been much anæmia, as in cases where death has terminated a protracted illness, in phthisis for example, or in persons who have died of hemorrhage, or after excessive venesection, the nervous centres will be found to be small, and the liquid in large quantity. In extreme cases of

lead cachexy, in which the nutrition of the nervous and muscular tissues is materially diminished, I have observed similar appearances. And, when any partial atrophy of either the brain or the spinal cord has occurred, there will invariably be found, at a point corresponding to it on the exterior of the organ, a local accumulation of fluid, occupying a depression on its surface, which has been caused by the giving way of the nervous substance within.

"On the other hand, an increase in the quantity of the nervous substance, or an enlargement of the brain or spinal cord, consequent on an undue injection of their blood-vessels, is invariably accompanied with a diminution in the quantity of this fluid, or with the total absence of it. In hypertrophy of the brain, no fluid is found in the subarachnoid space, and very little or none in the ventricles. In cases of tumour of the brain encroaching upon the cranial cavity, we find no fluid; and the same is observed where chronic inflammation of the brain has given rise to a new deposit, which increases the bulk and the density of the cranial contents. In all cases where a considerable quantity of fluid has accumulated within the ventricles, that upon the surface is either greatly diminished or entirely disappeared. In the ordinary hydrocephalus internus of children, fluid is never found on the exterior of the brain.

When an arrest in the development of any portion of the cerebro-spinal axis has taken place, the space which ought to be occupied by the organ of imperfect growth is filled by liquid. In examining the heads of idiots, we always find a considerable quantity of sub-arachnoid fluid, either general or partial, if a portion only of the brain be deficient." (p. 50.)

We fully agree with Dr. Todd in his general deduction, that the preternatural increase of this fluid should be usually regarded as secondary to the diminished size of the cerebro-spinal centre itself, or to the diminished quantity of blood in the vessels, and that it has little or no direct connexion with the manifestation of peculiar symptoms during life, in the great majority of instances. The complete investment of the encephalon by an unyielding bony case, obviously places it in a different condition from any other organ, since any diminution in its bulk must leave a vacuum (which Nature, here at least, seems to abhor), if the space be not filled up with fluid. But it would be absurd to deny that the cerebro-spinal fluid occasionally undergoes a preternatural increase, whilst the brain experiences no diminution in bulk, or itself becomes enlarged. This increase, however, rarely takes place in the sub-arachnoid fluid of the exterior of the brain, being much more common in the fluid within the lateral ventricles; the walls of which acquire, after they have been long subjected to its pressure, a preternatural degree of firmness, so as not to collapse when laid open. In these views Dr. Todd accords with the opinions first brought forward by the late Dr. Sims, in his valuable paper on serous effusion in the brain.

Dr. Todd has minutely examined the structure of the Pacchionian bodies, and considers them as morbid structures originating in a deposit of lymph among the vessels of the pia mater, which pushes the arachnoid before it as an investing sac. In some instances the granular mass is only partially covered, and then it causes only a slight projection on the surface of the visceral layer of arachnoid; but in others the mass is completely covered, and a stalk is gradually formed; and when several granular masses have been deposited immediately contiguous to each other, they may all be attached by a cluster to the same stem. The membranous sacs of some

of the bodies have epithelial particles upon their surface, whereby the derivation of these sacs from the arachnoid membrane is made apparent.

"The great frequency with which these bodies are met with in the various situations above mentioned, has induced many, even in the present day, to regard them as normal structures, the physiological office of which is as yet unknown. But there are many facts which strongly militate against such a conclusion. In the first place it may be observed, that the Pacchionian bodies never occur in the earliest periods of life. In the course of a long experience in anatomical inves tigations, I have never seen them at a period antecedent to six years. The brothers Wenzel, who made a series of special examinations, with a view to determine this question, make the following statement :-In children, from birth to the third year, these bodies, if they ever occur, must be very few. From the seventh to the twentieth year, they sometimes are numerous. From the latter period to the fortieth year, their number is considerable, and the nearer we approach the fortieth year, the greater does it become. Lastly, from the fortieth to the one hundredth year, these bodies are found in great numbers.

"It must further be remarked, that even at those periods of life when the Pacchionian bodies are found in greatest numbers, cases frequently occur in which no trace of them can be found. There is likewise the greatest variety, as to their number and size, in different individuals of the same age. It has always occurred to me to find them most numerous in cases, where I had reason to know that the brain had been subject to frequent excitement during life. In persons addicted to the excessive use of spirituous liquors, in those of irritable temperament, and who had frequently been a prey to violent and exciting passions, they are almost uniformly highly developed. The Pacchionian bodies are peculiar to the human subject, nothing similar to them has been found in any of the inferior classes of animals.

"In reference, then, to the question, what is the nature of these bodies, I have no difficulty in stating my opinion that the evidence greatly preponderates in favour of their morbid origin: that they are the product of a chronic, very gradual, irritation, due to more or less frequent functional excitement of the brain itself. It is not unlikely that the friction to which the opposed surfaces of the arachnoid are continually subjected in the movements of the brain, especially when they are of a more rapid and violent kind, as under states of cerebral excitement, may contribute to the development of many of the appearances connected with these bodies. The opaque spots, which are of such frequent occurrence upon the surface of the heart, may be quoted as an example of a morbid change, very commonly met with, and resulting probably from the friction against each other of opposed serous surfaces. Were the Pacchionian bodies normal structures, they would not be so frequently absent from brains which afforded every other indication of being in a healthy state; nor should we find opacity of the arachnoid (a decidedly unhealthy condition) so commonly coexistent with the full development of them. Again, were they a necessary part of the healthy organism, we might expect to find them more constant as regards size, number, and the extent of surface over which they were placed." (p. 60.)

This last argument is, perhaps, the weakest; since we do find an almost equal variation in the number and situation of the curious Pacinian corpuscles; which can hardly be regarded in the light of morbid

structures.

The description of the vesicular nervous matter, which is peculiarly full and lucid, closes with the following well-expressed queries:

"The great simplicity in the form of the elements of the gray nervous matter is one of its most remarkable characteristics. That a tissue, which plays the