(_g_) Visceral anæsthesia shows itself in the ordinary way by loss of that feeble degree of common sensibility which the internal organs possess, and also by impairment of their special functions, giving rise to anorexia, hydroadipsia, retention of feces and urine, loss of sexual feeling (without progenital anæsthesia). Of course, these symptoms may be due to other conditions, and each case must be carefully studied. In the insane, visceral anæsthesia gives rise to delusions of emptiness, destruction of organs, and even, if coinciding with general cutaneous anæsthesia, to the notion that the body is dead or absent. A singular phenomenon often witnessed is retardation in the transmission of an impression (usually a painful one). Thus, in testing the sensibility of the skin of the legs in tabetic patients, it is observed that instead of the normal, almost instantaneous, appreciation of the impression made by a needle-point, there is a lapse of two, five, ten, or even sixty seconds between the pricking and the signal of sensation by the patient. It should always be determined in such cases whether the retardation is peripheral and actual, or central and due to psychic conditions (dementia, absorption in a delusional state). Thus, in a case of profound melancholia we may observe extreme slowness and dulness of sensory impressions or complete anæsthesia; but the symptoms would have a very different significance, diagnostic and prognostic, from the same noted in a mentally clear patient. An important result of impairment of sensibility is a reduction or loss of reflex movements originating from the area or organ which is anæsthetic. This is shown in anæsthesia of the distribution of the trigeminus {37} when the reflex protecting movements of the eyelids no longer take place, in atrophy of the optic nerve when the pupillary reflex actions are lost. In posterior spinal sclerosis we see several illustrations of this law: progressive degeneration of nerve-fibres in the posterior root-zones of the spinal cord, causing loss of patellar reflex, of vesical, rectal, and sexual reflexes, and in most cases of cilio-spinal reflexes and of muscular tonus. In these and analogous conditions one arc of the reflex mechanism is deranged, centripetal conduction is interfered with, and the reflex motor discharge can no longer be evoked. That a similar pathological condition occurs in the cerebral mechanism, and may serve to explain many psychic symptoms, is very probable.