Conditions of sexual coldness, or apathy, physiological in character, are not uncommon; being found more frequently in women than men. They are as a rule due to psychical, rather than material causes; and are manifested in disinclination for the sexual act, absence of pleasurable excitation, and such other accompaniments as show them to be, usually, of a congenital character. If diminution of the sexual passion be not a somatic one, dependent on age and natural organic degeneration, a pathological cause may properly be inferred. As previously pointed out, however, diminution of sexual lust frequently depends on certain psychical and moral factors which are too frequently overlooked in considering the vita sexualis.
Education, hard study, emotional depression, anxiety, intense physical effort, all exercise a marked influence in lessening sexual desire; and continence itself, while at first stimulating', afterwards induces a marked abatement of secretory activity in the generative glands, and a consequent diminution of sexual desire.
Disturbances of nutrition are also prominent among the peripheral causes. Conditions of muscular atrophy—so called marasmus—may likewise be mentioned as causative; and alcoholic and drug intoxication produces it; not centrally, as frequently supposed, but peripherally, by over-stimulation and subsequent exhaustion of the neuro-sexual mechanism. Interference with that mechanism, arising from a central source, may usually be traced to degenerative changes in, or near, the genito-spinal center in the cord; functionally, to hysteria, which may be a manifestation of central anesthesia; and to those forms of emotional insanity characterized by melancholia, and hypochondriasis, as well as to the dementia paralytica of cortical disease.