At the age of 11½ years in 1 case. From this collection of _Gebhard’s_ we learn that in one case menstruation already existed at birth, and that in a large number of cases it occurred before the expiration of the first year. In many cases the development of the breasts preceded the appearance of menstruation, and was noticed from the time of birth. The vulva also early exhibited the characteristics seen in the sexually mature woman. Further, a high body-weight, great development of fat, and early dentition, were usually seen in these cases, in which, however, the intellectual development was not in correspondence with that of the body. In several of these cases of premature puberty, moreover, sexual intercourse and even parturition occurred at a very early age. A girl in whom menstruation began at the age of one year, gave birth to a child when she was ten years old (_Montgomery_). A girl who began to menstruate at the age of nine years, became pregnant very shortly afterward (_d’Outreport_). The well-known case recorded by _Haller_, in which at birth the pubic hair was already grown, and in which menstruation began at the age of two years, was also one of very early pregnancy, the girl giving birth to a child when nine years old. Another girl in whom at birth the pubes were already covered with hair began to menstruate when four years old, copulated regularly from the age of eight, and at nine years became pregnant, and was delivered of a vesicular mole with an embryo (_Molitor_). A girl began to menstruate at the age of two, had a growth of hair on the pubes and developed mammæ at the age of three, and became pregnant at the age of eight (_Carus_). With these cases must be classed that observed by _Martin_ in America of a woman who was a grandmother at the age of twenty-six. _Lantier_, in his Travels in Greece, speaks of a mother of twenty-five with a daughter of thirteen. Observations made by _Kussmaul_ and by _Hofmeier_ prove that in many cases changes in the ovaries form the probable cause of precocious menstruation and the other phenomena of premature puberty. In one case of _Hofmeier’s_, for instance, of a girl of five with precocious menstruation, the removal of a rapidly growing ovarian tumor was followed by the cessation of menstruation, and the pubic hair, which had been shaved off, did not grow again. Abnormally early puberty related to the early practice of sexual intercourse is seen in many prostitutes. This is shown by the following figures relating to 150 prostitutes in Russia. Sexual intercourse began: In 1 prostitute at the age of 9 years. In 1 prostitute at the age of 10 years. In 4 prostitutes at the age of 12 years. In 12 prostitutes at the age of 13 years. In 14 prostitutes at the age of 14 years. In 33 prostitutes at the age of 15 years. In 36 prostitutes at the age of 16 years.