In Paris 14 years, 6 months. In small towns 14 years, 9 months. In country districts 14 years, 10 months. Similarly it was found by _Ravn_ that menstruation first occurred: In Copenhagen at the average age of 15 years, 7 months. In industrial towns 15 years, 4 months. In country districts 16 years, 5 months. _Mayer_ states that the average age at which the first menstruation occurs is: In townswomen 15.98 years. In countrywomen 15.20 years. In Italy, according to _Calderini_, in a thousand instances, menstruation begins at the age of 14 in 280, at the age of 15 in 219, at the age of 13 in 205, at the age of 12 in 116, at the age of 16 in 89, at the age of 17 in 55, at the age of 18 in 14, at the age of 11 in 7, at the age of 10 in 6, and at the age of 20 in 6 instances. In girls attending town schools, the first menstruation most commonly occurs in the months of June and August; but in girls attending country schools most commonly in the spring months. A certain hereditary predisposition is so far determinant in the matter of the early or late onset of the first menstruation, that from a knowledge of the age at which menstruation began in the mother, we are able with great probability to predict the age at which it will begin in the daughter. Among fifty cases which I investigated with this point in view, I found forty-one in which the daughters of mothers who had begun to menstruate early began themselves to menstruate early, usually indeed in about the same year of life; or conversely that when the mother had begun to menstruate late, late onset of menstruation was usually to be observed in the daughter also. _Tilt_ relates a case in which a woman began to menstruate at the age of fourteen, and her daughter and granddaughter both began to menstruate at the same age. _Courty_ observed a mother who began to menstruate at the age of eleven, and whose eight daughters all began to menstruate at the same age. Gynecologists agree in stating that girls of sanguine temperament and powerful constitution begin to menstruate earlier than weakly and phlegmatic individuals. _Tilt_ describes a peculiar ovarian temperament, in which menstruation begins early; such women have as a rule striking nervous sensibilities, with a dark complexion and glistening, longing eyes, always surrounded by dark rings. The opinion is general that in girls with black hair, dark eyes, thick skin, and dark complexion, menstruation begins earlier than in blondes with blue eyes and delicate white skin. _Brierre de Boismont_ states in this connection that not fair hair only, but also chestnut-tinted locks, indicate a late onset of menstruation. _L. Mayer_ found that: _Of blondes._ _Of brunettes._