precocious one--of commencing puberty; the remaining 3 at 15 and 16; the average age of commencing masturbation, it may be added, was 11, while that of the first sexual intercourse was 15.[300] In a larger group of 180 prostitutes, belonging to Genoa, Turin, Venice, etc., and among 23 "elegant cocottes," of Italian and foreign origin, Moraglia obtained the same results; everyone admitted masturbation, and not less than 113 preferred masturbation, either solitary or mutual, to normal coitus. Among the insane, as among idiots, masturbation is somewhat more common among males, according to Blandford, in England, as also it is in Germany, according to Näcke,[301] while Venturi, in Italy, has found it more common among females.[302] There appears to be no limit to the age at which spontaneous masturbation may begin to appear. I have already referred to the practice of thigh-rubbing in infants under one year of age. J.P. West has reported in detail 3 cases of masturbation in very early childhood--2 in girls, 1 in a boy--in which the practice had been acquired spontaneously, and could only be traced to some source of irritation in pressure from clothing, etc.[303] Probably there is often in such cases some hereditary lack of nervous stability. Block has recorded the case of a girl--very bright for her age, though excessively shy and taciturn--who began masturbating spontaneously at the age of two; in this case the mother had masturbated all her life, even continuing the practice after marriage, and, though she succeeded in refraining during pregnancy, her thoughts still dwelt upon it, while the maternal grandmother had died in an asylum from "masturbatory insanity." Freud considers that auto-erotic manifestations are common in infancy, and that the rhythmic function of any sensitive spot, primarily the lips, may easily pass into masturbation. He regards the infantile manifestations of which thumb-sucking is the most familiar example (Lüdeln or Lutschen in German) as auto-erotic, the germ arising in sucking the breasts since the lips are an erogenous zone which may easily be excited by the warm stream of milk. But this only occurs, he points out, in subjects in whom the sensitivity of the lip zone is heightened and especially in those who at a later age are liable to become hysterical.[304] Shuttleworth also points out that the mere fidgetiness of a neurotic infant, even when only a few months old, sometimes leads to the spontaneous and accidental discovery of pleasurable sexual sensations, which for a time appease the restlessness of nervous instability, though a vicious circle is thus established. He has found that, especially among quite young girls of neurotic heredity, self-induced excitement, often in the form of thigh-friction, is more common than is usually supposed.[305]