II. SPINAL. }1. Affections of the erection centre. }2. Affections of the ejaculation centre. }1. Paradoxia. }2. Anæsthesia. III. CEREBRAL. }3. Hyperæsthesia. }4. Paræsthesia. II. SPINAL NEUROSES. _1. Affections of the Erection Centre._ (a) _Irritation_ (priapism) arises reflexly from peripheral sensory irritants (_e.g._, gonorrhœa); directly, from organic irritation of the nerve-tracts from the brain to the erection centre (spinal disease in the lower cervical and upper dorsal regions), or of the centre itself (certain poisons); or from psychical irritation. In the latter case satyriasis exists, _i.e._, abnormal duration of erection, with libido sexualis. In simply reflex or direct organic irritation, libido sexualis may be wanting, and the priapism be accompanied by unpleasant feelings. (b) _Paralysis_ from destruction of the centre or of the nerve-tracts (nervi erigentes), in diseases of the spinal cord (paralytic impotence). A milder form is that of lessened excitability of the centre, resulting from overstimulation (in sexual excesses, especially in onanism), or from alcoholic intoxication, abuse of bromides, etc. It may be accompanied by cerebral anæsthesia, and often with anæsthesia of the external genitals. Cerebral hyperæsthesia is here more frequent (increased libido sexualis, lust). A peculiar form of diminished excitability is shown in those cases where the centre responds only to certain stimuli. Thus there are men for whom sexual contact with their virtuous wives does not supply the necessary stimulus for the excitation of an erection, but in whom it occurs when the act is attempted with a prostitute, or in the form of some unnatural sexual act. As far as psychical stimuli are here concerned, they may be inadequate (_v. infra_, paræsthesia and perversion of sexual instinct). (c) _Inhibition._ The erection centre may become functionally incapable as a result of cerebral influence. This inhibitory influence is an emotion (disgust, fear of contagion), or an idea[30] of impotence. There are many men in the first condition who have an unconquerable loathing for their wives, or fear of infection, or are suffering with perverse sexual feelings. In the latter condition are neuropathic individuals (neurasthenics, hypochondriacs), frequently weakened sexually (masturbators), who have reason, or think they have, to mistrust their sexual power. This idea acts as an inhibitory concept, and makes the act with the person concerned of the opposite sex temporarily or absolutely impossible.