{ Prostitutes. Emotional States { Criminals. { Unstable. Neuralgia { External. { Internal. { { Symptomatical. { Acute Insanity { Idiopathic. { { Alcoholic. Psychoses { Imbecility { Idiocy { General Insanity. { Chronic Insanity { Dementia. { Partial Insanity. { Congenital { Blindness. Special and General Conditions of the Senses { Anæsthesiæ. { Deafness. { Hyperæsthesiæ. Nutritional Defect. The extensive studies of Niepce,[28] Vogt,[29] and others on idiot biology sought to show that the brain was not merely arrested in development, but sometimes reverted even as low as the sauropsida type (reptiles and birds). Grohmann,[30] as early as 1820, had "often been impressed in criminals, especially in those of defective development, by the prominent ears, the shape of the cranium, the projecting cheek-bones, the large lower jaws, the deeply placed eyes, the shifty, animal-like gaze." Maudsley[31] observes that in the case of such an extreme morbid variety as a congenital idiot we have to do with a defective nervous organisation. Marchand, in the brain of two idiots of European descent, found the convolutions fewer in number, individually less complex, broader and smoother than in the apes. The condition results neither from atrophy nor mere arrest of growth, but consists essentially in an imperfect evolution of the cerebral hemispheres or their parts, dependent on an arrest of development. The proportion of the weight of brain to that of body is extraordinarily diminished. With the brain of the orang type comes a corresponding defect of function. With this animal type of brain in idiocy sometimes appear animal traits and instincts. One class of idiots is justly designated theroid, so brute-like are its members. The human brain in the course of foetal development passes through the same stages as other vertebrate brains, and to some extent these transitional stages resemble the permanent forms of their brain. Summing up, as it were, in itself the leading forms of vertebrate type, there is truly a brute brain within the man's, and when the latter stops short of its characteristic development, it is natural that it should manifest only its most primitive functions.