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But it is not epilepsy alone, to which the theory of spasmodic contraction of certain blood vessels, with excessive dilatation of others, depending upon a state of reflex excitation or of paralysis of the vaso-motor nerves, is applicable; for various other forms of nervous disorder may be attributed to it with great probability. Among these M, Brown-Séquard mentions various forms of insanity, of vertigo, of hallucinations and illusions, and also extasis, catalepsy, hysteria, chorea, hydrophobia, tetanus, local cramps, and even the general paralysis connected with insanity; which, as pathological evidence has long since been shown to indicate,* are often due to irritations starting from a centripetal nerve, that are frequently slightly felt or even unfelt; and which may then be promptly cured, like epilepsy, by the simple removal of the irritating agency. And it seems to us more than probable that the actions of many kinds of poisons, especially such as produce their chief results through the nervous system, involve the like change as their primary phenomena. There can be little doubt that some of the most potent of these act (as we have seen that chloroform probably does) directly upon the heart after the manner of shock; such appears to be the case with alcohol, when introduced into the stomach in a state of high concentration, hydrocyanic acid, aconitine, nicotine, and sometimes even with arsenic. The extraordinary variety of the combinations of anesthesia and hyperæsthesia, which characterizes some forms of lead-poisoning, seems to us, like the corresponding vagaries of hysteric disorder, to be better accounted for on the idea of local "spasm of the extreme vessels" than on any other. And even in the action of certain narcotics, especially opium, there are phenomena which, as it seems to us, can be better explained in this manner than in any other. If tetanus is ever attributable to this cause, the artificial tetanus induced by strychnia has its origin by the same reflex agency; and this, we believe we may state, M. Brown-Séquard expects to be able ere long to prove. We conclude this part of our subject by expressing a strong belief that the action of the vaso-motor nerves is one of the most important subjects that can engage the attention of physiologists and pathologists; and that it will be found to afford the key to a great number of phenomena, our very familiarity with which seems to be the cause why they have hitherto received so little attention. As one example of what we mean, we may refer to the extreme coldness of the extremities, often suddenly coming on, and as suddenly departing, to which many persons are subject (especially if they work their brains too severely), notwithstanding that the general circulation is by no means deficient in vigour.
VI. The Influence of the Nervous System upon the Nutritive and Secretory Operations, and especially its reflex action, are very fully discussed by M. Brown-Séquard, who does net omit to expose the fallacy of the claims to discovery on this subject which have been set up by Dr. Marshall Hall and by Dr. H. F. Campbell of Georgia (U.S.) For whilst freely conceding that Dr. Campbell was the first to intro* See especially Dr. Laycock's Treatise on the Nervous Diseases of Women, passim.
duce in science the hypothesis that there exists a secretory and excitosecretory system of nerves, he points out that neither he nor Dr. M. Hall adduced a single fact to prove its existence, and that both these physiologists seem to have been unaware that reflex changes in nutrition and secretion were perfectly known, and that the question was, not to prove that there are such reflex phenomena, but whether they are to be explained by a reflex influence on blood vessels or otherwise. He gives due credit to our own Whytt for having shown that the natural and morbid sympathies, in regard alike to movement, to nutrition, and to secretion, are reflex phenomena, and that the share of the blood vessels is very great in these phenomena; and he specially alludes, among modern works, to Müller's Handbook of Physiology,' Stilling's Treatise on Spinal Irritation,' and various writings of Henle in 1840 and 1841 (to which we would add Dr. Laycock's Treatise on the Nervous Diseases of Women'), as having advanced the subject much further than Dr. Campbell did in his first publication. The portion of M. Brown-Séquard's 'Lectures' which is devoted to this enquiry, contains a very able and elaborate summary of various recent contributions, chiefly furnished by pathological observation, by which the doctrine is placed upon a more secure and extended basis than that on which it previously rested; but since, of these contributions, a very small part is furnished by himself, we do not think it requisite to discuss this portion of his Lectures as fully as we have done the preceding; and shall limit ourselves to the citation of a few of the facts adduced by him, which seem to us of special novelty or interest.
Under the head of Reflex Secretions, we learn that M. Castorani has recently confirmed, by decisive facts, the view that it is not through the optic nerve, but through the exalted excitability of the trigeminal, that the secretion of tears is increased in photophobia when the eye is exposed to the stimulus of light; and that M. Deslandes has observed that a man totally blind had an abundant secretion of tears every time he passed from a dark place to a light one. The shedding of tears under the influence of irritation of other parts than the eye and nose, is said by M. Brown-Séquard to be less and less the further the irritation is from the eye; in experimenting upon himself he has found that the pinching of the neck or of the back parts of the head scarcely produces lachrymation, whilst pinching of the face produces it more and more the nearer the eye the irritation is made; and the same result shows itself in cases of neuralgia, the lachrymation which is a frequent concomitant of this affection in the fifth pair being specially produced by neuralgia of its supra-orbital branch. The following experiment performed by M. Brown-Séquard to test the reflex influence of the nervous system on the urinary secretion, is valuable for the precision of its results:
"We place a tube in one of the ureters of a dog, so as to know what is the quantity of urine flowing out in a given time, after the dog has recovered from the shock of the operation. We then pinch the internal surface of the abdominal wall, in a part receiving its nerves from one of the first lumbar pairs; and almost at once we find that the secretion of urine is cither stopped
or very much diminished. It is not in consequence of a change in the circu ation due to the pain caused by the pinching, that the secretion is so much diminished; as we find the same thing taking place whether the spinal cord in the dorsal region has been divided transversely or be left in communication with the encephalon. And if the part of the cord which gives origin to the lumbar pairs of nerves has been destroyed-in which case the urinary secretion, after a short stoppage, becomes normal (as to its quantity, at least), and is rather more than less abundant than before, we find that the irritation of the abdominal wall remains without effect upon the kidney. We must conclude, therefore, that when the spinal cord exists, the irritation passes through it; or, in other words, that the stoppage of the urinary secretion is due to a reflex action of the spinal cord. I have ascertained, also, that it is through the spinal cord, and by a reflex action, that the irritation of one kidney acts upon the other, sometimes to diminish, sometimes to increase, its secretion."
It is, of course, open to question whether the influence which the nervous system undoubtedly exerts over the quantity of the secretions, may not be due simply to its control over the calibre of the bloodvessels; and this, at first view, might seem the more probable, since increase of various secretions of glands and membranes of the head is noticed as one of the results of section of the cervical sympathetic. But it is to be borne in mind, that this increase proceeds from paralysis of the vaso-motor nerves, which, by permitting a greater afflux of blood, augments the general vital activity of the parts through which passes; whilst it is antagonized by excitation of those nerves, which, by causing contraction of the vessels, brings back the secretions to their normal condition. Now it would seem unlikely that the various forms of stimulation, with whose action in augmenting the lachrymal, the gastric, the mammary, and other secretions, every one is familiar, should exert their influence by paralysing the vaso-motor nerves; and we seem to have, in the experiment just cited, a very clear indication that the augmentation of the secretion is due to a reflex stimulating influence conveyed by the nerves of the gland, as the result of an excitation applied to a remote part. This inference fully accords with the result previously obtained by Cl. Bernard and Czermak in regard to the salivary secretion, which they have shown to be augmented by excitation of the lingual nerve; and it also harmonizes very remarkably with the doctrine often maintained in the pages of this Journal, as to the influence of augmentation in the functional activity of a part, in determining the afflux of blood to it.
It may now be accounted as an established fact that, the nutrition of certain parts is often affected in a very decided way by remote irritations, whose influence is transmitted through the nerves leading from the part irritated to the central organs, and is then reflected back from them towards the periphery. Of all the organs in the body, there is none which gives such evident and frequent instances of this kind of affection, as the eye. For notwithstanding the doubts of eminent physiologists like J. Müller, and of able oculists like Walther and Sichel, it must be obvious to any one who carefully weighs the evidence now collected, that when the supra-orbital nerve has been crushed or injured, in such a way that it remains irritated, an inflam
mation or some other affection of the corresponding eye is very apt to supervene; and further, that when an eye is the seat of a violent inflammation, and particularly if this be of traumatic origin, the other eye is extremely liable to become affected. We have ourselves seen a large number of cases in which amaurosis followed an injury to the supra-orbital nerve; and one of these was peculiar in this respect, that the injury consisted in the lodgment of a single shot-pellet in that nerve very near its point of emersion on the forehead, thus meeting the objection of Müller and Sichel that the amaurosis following a blow on the forehead may be fairly attributed to the commotion of the eye and optic nerve. Dr. Alcock, moreover, showed that injuries to the infra-orbital nerve are not less liable to produce results of this kind, than those of the supra-orbital. We have also ourselves seen many cases in which amaurosis and cataract, together or separately, having supervened in one eye upon a blow, have appeared after a time in the other. And M. Brown-Séquard very correctly states that the danger to the second eye of a long continuance of traumatic irritation has been so fully recognised in this country, that the extirpation of the wounded eye to save the other has now become a recognised practice.
Among analogous phenomena occurring elsewhere, M. BrownSéquard lays particular stress on the disordered nutrition of one or more of the principal viscera of the head, thorax, or abdomen, which, as the observations of Mr. Long and Mr. Curling demonstrate, is one of the most common sequences of severe burns of the external surface. The whole collection of facts he has brought together upon this subject is extremely well worthy of attention; especially as many of them are drawn from sources but little known in this country; but our limited space warns us to forbear from citing any of them; and we must content ourselves with endorsing his remark that changes of this kind are not explicable by simple augmentation or diminution in the supply of blood, such as may be produced by an action of the vasomotor nerves in modifying the calibre of the blood-vessels, but point to an influence exercised through the nerves upon the vital properties of the tissues themselves. We see, for example, that after section of the cervical sympathetic, the continued augmentation in the supply of blood to the eye, ear, &c., does not itself produce inflammation; and although this morbid process is produced much more easily in these parts than in others, it does not supervene spontaneously, but requires some special cause in addition to the alteration of the supply of blood and the paralysis of the vaso-motor nerves.
We shall bring our survey to a conclusion by quoting the suggestions offered by M. Brown-Séquard as to the therapeutic applications of which the principle of the reflex action of the nervous system upon the nutritive functions seems most obviously susceptible; and in taking our leave of him for the present, we would offer him our hearty thanks for what he has already done for Physiology, and our cordial good wishes for his further success in the same useful and honourable
"1st. When we wish to produce a modification in the condition of any organ, we must apply the means of irritation that we prefer to the part of the skin or of the mucous membranes which have the most evident nervous relations with it. In most cases the parts acting with the greatest power upon another are those which receive their nerves from the same segment of the cerebro-spinal axis. If we wish, for instance, to act upon the kidney, the skin of the abdomen in its upper part is the best for the application of any kind of irritation. Do we wish to act on the eye, in cases of amaurosis due to insuf ficiency in the amount of blood, the irritation ought to be applied chiefly to the supra- or infra-orbitalis nerves. If the amaurosis coexists with hyperæmia, the irritation of those nerves must be avoided, and the means of revulsion ought to be applied on the back of the neck, so as to act on the spinal cord, and, through it, by the sympathetic nerve, which has on the eye an influence entirely different from that of the trigeminal nerve. In cases of diarrhoea, an influence upon the nerves of the bowels originating from nearly the middle of the dorsal region might be obtained by the irritation of the skin of the middle of the chest. The ovaries and the uterus being able to influence the nutrition of the mamma, and these glauds being able to act upon the genital organs, irritation will be applied to one group of these organs when we wish to act upon the other. In amenorrhoea, for instance, various means of irritation to the breast have produced menstruation. 2nd. The kinds of irritation which produce the most powerful effects are a great and sudden change of temperature, heat or cold, or the application of a very strong galvanic current. Frequent irritations, with periods of interruption between them, are better than permanent irritations. 3rd. The suppression of the cause of irritation, when a disease is produced by a reflex action, is of course the principal mode of treatment. In cases of paralysis, of anesthesia, or of a convulsive affection, &c., we must try to find out if there is an irritation on any centripetal nerve, and employ the most energetic means for its removal. But I must say that it is entirely useless to amputate a limb, or a part of it, as has been done sometimes in cases of convulsive affections produced by an external irritation. The section of a nerve will do as well,-and this is already proved by many cases,and perhaps, as I will show in my last lecture, a simpler means might be employed. Time pressing me to go on, I will only add here that in cases of reflex congestions or inflammations due to burns or to congelation, or, in fact, in any case in which we have to avoid a reflex influence, we must diminish the reflex faculty of the spinal cord and encephalon, and we know no medicine having so much power in this respect as belladonna."
Copy of the Statistical Report of the Health of the Royal Navy for the
26 July, 1858.
THE Statistical Reports on the Health of the Royal Navy, drawn up from Returns lodged in the office of the Director-General, commenced in the year 1830, and have since that time been printed at irregular intervals. Up to 1836, inclusive, they were brought out under the care of Dr. Wilson, and he was succeeded by Dr. Bryson, who still continues to superintend them. The labours of both these gentlemen have been accomplished in a manner highly creditable to themselves, and conducive to the attainment of the important objects in view.