236 REPRODUCTION, PUBERTY AND LONGEVITY. 



We have also an explanation of why some animals are higher in 

 the scale than others, and we have placed in our hands a ready 

 means for raising the standard of the human race and for developing 

 our domestic animals. 



It having been shown that increased age in parents is an ab- 

 solutely essential element in the progressive evolution of intellect, 

 and that there is no limit to the amount of age which may be 

 advantageously added to parents before the time of reproduction 

 provided these parents maintain their physical health and vigor, 

 it becomes interesting to know what steps may be taken for ad- 

 vancement along this line. The first step would, of course, be 

 delaying the age of puberty, as such delay would shut off the very 

 early reproduction, and there are very good reasons for thinking 

 that as much time is added to the latter part of the reproductive 

 period as is subtracted from the first part by delay. 



THE AGE OF PUBERTY. 



Ouatrefages 1 has given us statistics as to the age of female puber- 

 ty, and from these it appears the time of arrival at puberty is more or 

 less affected by climate, by quality and amount of nutrition, and 

 by mode of life. For Paris he states that the average age of female 

 puberty is, for the upper classes, 13 years and 8 months; for the 

 middle class, 14 years and 5 months, and for the lower classes 14 

 years and 10 months. Country girls are behind city girls four and 

 one-half months for Paris and eight and one-half months for 

 Strassburg. For Toulon the average age is given as 14 years and 

 5 days, for Strassburg as 16 years and 54 days. Between these 

 two cities there is a difference of three degrees of latitude and five 

 degrees of mean temperature; Toulon is equable and sunny, and 

 (i) The Human Species, p. 416. 



