300 GENERATION. 



and take on a new stage of development ; 1 Graafian follicles 

 enlarge, and one or more approach the condition favorable to 

 rupture and the discharge of ova. At this time, also, certain 

 changes are observed in the moral, as well as in the physical 

 attributes of the female. There is then a sort of indefinite 

 consciousness of a capacity for new functions, with an inde- 

 scribable change in feeling for the opposite sex, due to the 

 first development of sexual instincts. The female becomes 

 capable of impregnation, and continues so, in the absence of 

 pathological conditions, until the cessation of the menses. 



It is a commonly-recognized fact that the age of puberty 

 is earlier in warm than in cold climates ; and numerous in- 

 stances are on record, in which the menses have appeared ex- 

 ceptionally, much before the usual period. Generally, at the 

 age of forty or forty-five, the menstrual flow becomes irregu- 

 lar ; it occasionally loses its sanguineous character, and it usu- 

 ally ceases at about the age of fifty years. Sometimes it is 

 said that the menses return, with a second period of fecundity, 

 though this is rare. 2 According to most writers, while climate 

 has a certain influence over the time of cessation as well as 

 the first appearance of the menses, this is not very marked. 

 "When the menses appear early in life, they usually cease at a 

 correspondingly early period ; but this is by no means con- 

 stant. There are, also, numerous exceptions to the ordinary 

 limits to the period of fecundity. Haller observed a case of 

 a young girl, nine years of age, who had menstruated for sev- 

 eral years, and others, who had become pregnant at nine, ten, 

 and twelve years. He also quotes cases of women who have 

 been fruitful at from fifty-four to seventy years of age. 8 

 Other instances of this kind are on record,* which it is un- 



1 For an account of the changes in the mammary glands at puberty, see vol. 

 iii., Secretion, p. 75. 



2 Cases of this kind were noted by Haller. (Elementa Physiologies, Bernae, 

 1765, tomus vii., pars ii., p. 141.) 



8 HALLER, op. tit., pp. 139, 142. 



4 In a recent publication, several interesting examples are given of early men- 

 struation and conception. (HARRIS, Early Pregnancy. American Journal of 



