Whichever of the terms, “inhibitory influence” (Handfield Jones and Lister), “reflex relaxation” (Brinton), or “reflex paralysis” (Brown-Séquard), be used, the fact is ceded by all, that “the energetic operation of an afferent nerve” (Lister), or some impression acting injuriously on an afferent nerve (Handfield Jones), or, again, “an actually existing irritation” (Brown-Séquard), exerts an injurious effect on its nerve centre, this state being, as Dr. Brown-Séquard thinks, increased or diminished according to the activity of the irritation, and ceasing with its entire removal, or, more probably, as Dr. Handfield Jones affirms, persisting after the cessation of the cause which has morbidly affected it. This latter view appears to me the more generally correct one, because it can hardly be expected that a gradual disease will be suddenly removed, there having been no time for recovery of nerve power.

In Dr. Handfield Jones’s Lumleian Lectures, delivered last year before the College of Physicians, he thus sums up his views on this subject:—“The essential idea of the inhibitory theory is, that an impression conveyed to a nervous centre by afferent nerves may weaken or paralyze, instead of exciting, its action, either from the congenital or acquired debility and sensitiveness of the nerve itself, or because the impression is unduly intense or absolutely injurious. Both these things have in every case to be considered—viz., the state of the nerve force, and the kind and amount of impression, as the resulting phenomena will vary with the variation of either.”

Dr. Jones next takes it as a matter of certainty, “that a nervous centre may be more or less completely paralyzed without having undergone organic change, in consequence of some enfeebling morbid influence;” and quotes from Dr. Gull[[2]] “a most interesting instance of complete paraplegia induced by sexual excess, in which nothing abnormal could be detected in the cord, even by careful microscopy. This was paralysis from simple exhaustion.”

[2]. “Guy’s Hospital Reports,” 1858. Case xvii.

Still continuing, Dr. Jones draws attention to the anatomical fact of the remarkably close manner in which “the different nerve centres, or parts of a nerve centre, are connected by commissural fibres,” and how, “from a pathological point of view, the same connexion is often very manifest. The general exhaustion induced by excess of venery,” and other cases, “are examples which show how excessive consumption of nerve force in one part weakens it also in others; and this can only be adequately explained by the intricate commissural connexion between the various centres.”

The truth of all these views is well exemplified, as Dr. Kidd has stated, in cases of epilepsy, which “may originate only in irritation of bad teeth acting on the brain, or worms irritating the nerves of the stomach, and so on as to other peripheral irritations; the chief skill being to find out the spot from which the irritation radiates.”

A case is also quoted by Dr. Jones, in the Lumleian Lectures, as having occurred in the practice of Mr. Castle, of New York, where diseased teeth produced paraplegia, which soon ceased after their removal.

Long and frequent observation convinced me that a large number of affections peculiar to females, depended on loss of nerve power, and that this was produced by peripheral irritation, arising originally in some branches of the pudic nerve, more particularly the incident nerve supplying the clitoris, and sometimes the small branches which supply the vagina, perinæum, and anus.

Closer observation satisfied me that the greater or less severity of the functional affections observed, depended on the amount and length of irritation, and the consequent amount of loss of nerve power.

Nor are functional disorders the only consequence, but in some cases, severe organic lesions.