now seems to be reckoned among the accepted doctrines of physiology. As Dr. Brunton takes his illustration of the mechanism of the process from pathology, it may be concluded that he considers the same view to be applicable to morbid as well as to normal actions.

Admitting this, it may however be well to point out in what respects pathological differ from physiological inhibitory actions: (1) The immediate motors of the former are not normal and appropriate stimuli, but injurious irritants, or depressants. (2) The paralyses are not confined to vaso-motor nerves, but affect also musculo-motor, common and special sensory, and even the hemispheres themselves. (3) The districts affected are often non-coterminous with, perhaps remote from that occupied by the incident nerve and its ramifications. (4) The occurrence of pathological inhibition may depend not on an absolutely excessive or injurious irritation having been applied, but on the incident nerve, or the recipient centre, being previously in a morbid state, hyperæsthetic, or hyperexcitable. (5) The same irritation may affect (pathologically) different parts in different persons. (6) Physiological inhibition is essentially transitory; pathological continues as long as the irritation persists. (7) Physiological inhibition is requisite for the performance of some function; pathological conditionates disease, disorder of function.

Sufficient heed has not always been given to the difference which may exist between the effect of different kinds of excitants. Just as we know it is with mental influences, some of which exalt and intensify nerve-force, to a high degree, while others as powerfully depress it, so it is probably with physical. One which is appropriate in kind and degree may be a very beneficial stimulant; another which is too powerful or altogether pernicious will have the most opposite effect. Thus it certainly is with wine and electricity: both in suitable doses are recreative; both in excessive are ruinous to healthy life. A carious tooth and a warm condiment are no doubt both excitants of the same sensory nerve, but how very different are the impressions made on the nerve-centre in the two cases! All impressions on sensory nerves certainly do not paralyse the associated vaso-motor. Vasal nerve-centres appear to be

more readily paralysed than any other; which may depend partly on their being smaller, and therefore more easily deranged than larger. It may also be the case that the resulting hyperemia is more easily appreciated than diminutions in the force of muscular masses, or in the tactile faculty of the integument. Some morbid phenomena of inhibition produced by disease are almost as precise and significant as the results of experimentation. It may be well to enumerate a few for the sake of those to whom the idea is not familiar:

(1.) Crimson flushing of head, face, and neck from gastric irritation, itself perhaps depending on gastric hyperæsthesia, unilateral flushing and heat, sweating of face from loaded bowels, face hyperæmic and covered with sweat when prepuce was irritated in a case of preputial neuroma. (Vide Verneuil, Year-book Syd. Soc. 1862, p. 239.)

(2.) Salivary flux from uterine irritation in pregnancy, or from neuralgia of fifth, or from irritation of filaments of the vagi distributed to the oesophagus. (Vide Dr. Fussell's case in Lancet, 1873, ii. p. 625).

(3.) Paralysis of heart by gastric, intestinal, cutaneous, or urethral irritation, as in gastralgia, peritonitis, burns, and operations on the urethra.

(4.) Paralysis of vasal nerve-centres from stricture-splitting, with coma; temperature 107°6. (Vide Medical Times and Gazette, 1873, ii. p. 121).

(5.) Sensory paralysis, as in Roche's case (vide BrownSéquard's Phys. of Central Nervous System, p. 131,) and Sir Thomas Watson's case (Lectures, last edition, vol. i. p. 538).

(6.) Motor paralysis, vide instances of reflex paraplegia given by Brown-Séquard; a case, cited from Mr. Morgan, of stone in bladder, vide F. N. D. p. 140; a case of my own, at p. 115, of left hemiplegia cured by an emetic; case of same ceasing after delivery, vide p. 119; cases of palsy from exposure to cold; cases of paralysis of muscles of eye in neuralgia of fifth.

(7.) Cases of amaurosis from gastric or dental irritation. Those who hold with me that pain is a mode of sensory paralysis will see in the common instances of reflex, or remote pain, a phenomenon closely analogous to, if not identical with, inhibitory paralysis.

The first observer who entertained the idea of reflex paralysis of blood-vessels was, I believe, Henle, who proposed a theory to this effect that the nerves of the vessels are in antagonism with the nerves of animal life, especially with the centripetal, so that in proportion as the latter are excited, excitement ceases in the former.1 This view was adopted by Mr. Simon in his admirable lectures on pathology, where he says (p. 80) that "reflex-relaxation" (as he calls it) appears to him "the only plausible explanation of the condition of the larger blood-vessels in active hyperæmia, whether inflammatory or hypertrophic." Subsequently the views developed by Weber, Pflüger, Rosenthal, and Nasse, as to the existence of certain systems of inhibitory nerves, contributed to familiarise the minds of inquirers with the idea that one nerve might diminish the action of another. Lister's researches confirmed and corrected these views, showing that the same afferent nerve might enhance or inhibit, exalt or depress, the functions of the nervous centre on which it acts, according as the stimulus applied to it was mild or potent. His paper was published in 1858. Bernard's essay on the influence of paralysing reflex agencies is dated September 1864; Lovén's paper appeared in 1867; Rutherford's in 1870. My views were first published in February 1859 in the British Medical Journal, and subsequently developed more completely in my Lumleian Lectures, Medical Times and Gazette, 1865, and in F. N. D. 1864 and 1870. They have been well appreciated by Anstie, but are scarcely mentioned by anyone else. Brown-Séquard, in his lectures published in the Lancet, 1860 and 1861, laid great stress on the production of paralysis, either in the cord or in the brain, by remote irritation; ascribing it, however, rather to anæmiating spasm of the vessels of the paralysed centre than to a direct action of the afferent nerve on the nerve-cells. Though I differ from him on this point, I think he has contributed very highly, perhaps more than anyone else, to establish the doctrine of reflex or inhibitory paralysis. His extension of this view to those cases where head symptoms-paralysis, &c.--cannot be explained by any discoverable destruction of the organ of the will or of the conductors between it and the muscles, seems to me quite correct, and a step of no mean importance. Henle's Traité d'Anat. vol. ii. p. 58.

original view, important and suggestive though it be, and supported by Lovén's experiment, does not seem to be substantiated. All excitements of afferent nerves do not dilate blood-vessels. Cold operating reflexly certainly does not. Nor does heat invariably, for Trousseau found hot water a more efficient styptic in epistaxis. Neuralgic perturbation does not induce hyperæmia in the majority of cases. Local irritants generally confine the resultant hyperemia to the area on which they act, and produce no general flushing of the adjacent surface. Their action seems to be rather on the tissue than on the vessels. When the skin on being scratched with the finger-nail presents the "tache méningitique," it is difficult to think that the lines of redness can be produced by any paresis of vaso-motor nerves. If such occurred in a reflex manner, it surely could not be so limited in extent, but would appear as a more or less widespread flush, as in instances cited in my Lumleian Lectures. In five instances where I faradised the peroneal nerve with moist rheophores just below the head of the fibula for five minutes, no redness of the skin of the parts below was produced, and only in two or three some filling of one or two superficial veins. Galvanisation is known to be much more effective than faradisation in causing augmented blood-flow in the district traversed by the current.

On the whole it appears, I think, that my original view is correct that it is for the most part morbid excitation-irritation as opposed to stimulation—which produces reflex or inhibitory paralysis in any part. Some few instances there are of physiological inhibition, but these seem only to render it more probable that a similar effect can be produced pathologically. Lovén's experiment, on which much stress is laid, seems to me rather an instance of pathological than of physiological inhibition. If we think what a difference there must be between our rude experimental excitation of a nerve and the normal, we must admit that the conclusion arrived at by Mr. Lister, respecting the different effects of gentle and strong stimulation, is highly rational and probable.

1

ON THE THEORY OF COUNTER-IRRITATION.

BY JAMES ROSS, M.D.,

WATERFOOT,

NEAR

MANCHESTER.

(Read before the Manchester Medical Society, Feb. 4, 1874.)

COUNTER-IRRITATION may be defined as the application of an irritant to one part of the body in order to influence morbid action in its vicinity. But when an irritant is applied at a distance from the morbid part, such as a mustard foot-bath for head affections, it does not come within the scope of this definition. Near and distant irritation do not probably act upon the same principle, and they require different practical rules for their application; it will therefore be practically convenient to separate them in our classification. Revulsive is a very bad term if it be held to involve a theory of the action of distant irritation in the cure of disease; but the term has been long in use, and with care in explaining that its employment did not imply any theory, it might be usefully retained. But however this question may be settled, I only mean to discuss at present the action of irritants when applied in the vicinity of the disease.

I shall now mention briefly the local effects which follow the application of a counter-irritant. I say the effects, because the prejudicial effects must be noticed as well as the beneficial; since we have not only to frame positive rules for the application of counter-irritants, but also negative rules for abstaining under certain circumstances from their employment. indeed one of the first rules with regard to counter-irritants laid down in practical works is a negative one of this kind. The rule is do not apply a counter-irritant in the early stage

And