1016 



OP GENERATION. 



corresponds with the age of 25 years. It afterwards ascends to d, which is the maximum 

 of viability subsequently to the age of puberty ; this point is attained at the age of 30 



Fig. 277. 



Diagram representing the Comparative Viability of the Male and Female at different Ages. 



years, from which period, up to 50, the probability of life is greater in the Male than in 

 the Female. In the decline of life there seems little difference for the two sexes. 



1019. Similar diagrams have been constructed by Quetelet, to indicate 

 the relative Heights and Weights of the two sexes at different ages (Fig. 278). 



a. In regard to Height, it may be observed that the increase is most rapid in the first 

 year, and that it afterwards diminishes gradually; between the ages of 5 and 16 years, 

 the annual increase is very regular. The difference between the Height of the male and 

 Female, which has been already stated to present itself at birth, continues to increase 

 during infancy and youth; it is not very decided, however, until about the 15th year, after 

 which the growth of the Female proceeds at a much diminished rate, whilst that of the 

 Male continues in nearly the same degree, until about the age of 19 years. It appears, 

 then, that the Female comes to her full development, in regard to Height, earlier than does 

 the Male. It seems probable, from the observations of Quetelet, that the full Height of 

 the Male is not generally attained until the age of 25 years. At about the age of 50, 

 both Male and Female undergo a diminution of their stature, which continues during the 

 latter part of life. 



b. The proportional Weight of the two sexes at different periods corresponds pretty 

 closely with their height. Starting from birth, the predominance then exhibited by the 

 Male gradually increases during the first few years; but towards the period of puberty, 

 the proportional weight of the Female increases; and at the age of 12 years, there is no 

 difference between the two sexes in this respect. The weight of the Male, however, then 

 increases much more rapidly than that of the Female, especially between the ages of 15 

 and 20 years ; after the latter period, there is no considerable increase on the side of the 

 Male, though his maximum is not attained until the age of 40 ; and there is an absolute 

 diminution on the part of the Female, whose weight remains less during nearly the whole 



