(_B_) The organic mental diseases affecting the psychic functions (cerebro-psychoses), differing from (_A_) chiefly in being deeper-seated: (1) With motor symptoms of excitement (acute mania): (_a_) Mania furiosa (including mania transitoria); (_b_) mania gravis; (_c_) acute delirious mania. (2) With motor neuroses and symptoms resembling catalepsy, tetanus, and anergic stupor, or the various forms of Spannungsneurosen: (_a_) Melancholia attonita; (_b_) delusional stupor; (_c_) primary dementia (stupor), acute and chronic. (3) With progressive paralysis, the typical form of paralytic dementia. (_C_) The distinct lesions of the brain, giving rise secondarily to psychical disturbances. The modified paralyses or cerebral diseases in which dementia and paralysis are both observed clinically: (_a_) Meningo-periencephalitis, chronic and subacute; (_b_) pachymeningitis and hæmatoma; (_c_) diffuse encephalitis with sclerosis, without mental excitement and with mental excitement; (_d_) diffuse encephalitis with local softening, apoplexy, capillary aneurisms in groups or singly, multiple sclerosis; (_e_) diffuse encephalitis arising from foreign growths in the brain; (_f_) chronic {108} periencephalitis, with previous tabes dorsalis; tabic paralysis: (_g_) primary atrophy of the brain, with accompanying spinal tabes, tabic dementia; (_h_) syphilitic encephalitis, with disturbances of the mind. Krafft-Ebing's classification is as follows: _A_. Mental Diseases of the Normal Brain.—I. Psychoneuroses: 1. Primary, curable diseases: _a_, Melancholia—_α_, Simple melancholia; _β_, melancholia with stupor; _b_, Mania—_α_, Maniacal exaltation; _β_, acute mania; _c_, Stupidity (primary dementia) or curable dementia; _d_, confusional insanity (Wahnsinn). 2. Secondary, incurable diseases: _a_, Chronic delusional insanity; _b_, terminal dementia—_α_, with agitation; _β_, with apathy. II. Conditions of Mental Degeneration.—_a_, Constitutional affective insanity (folie raisonnante); _b_, moral insanity; _c_, primary monomania—_α_, With delusions of persecution; _β_, with delusions of ambition; _d_, with imperative conceptions; _e_, insanity from constitutional neuroses—_α_, epileptic; _β_, hysterical; _γ_, hypochondriacal; _f_, periodic insanity (folie circulaire). III. Diseases of the Brain with Mental Disturbances Predominating.—_a_, Paralytic dementia; _b_, cerebral syphilis; _c_, chronic alcoholism; _d_, senile dementia; _e_, acute delirium. _B_. Conditions of Arrested Mental Development.—Idiocy and cretinism.