524 



HUMAN BIOLOGY 



In these facts is to be found unquestionably one of the 

 basic reasons for the practice of contraception or birth 

 control in countries having what we are pleased to regard as 



THE LIVIHG POPU^L^TIOri 



Tlie 



50 6'Ovef 



Fig I. Approximate average distribution of living human population 



Frequencies are depicted as areas. 



a "high" state of civilization (see chapter xxii). As the 

 burden becomes more and more clearly recognized the 

 natural tendency is to attempt to reduce it by limiting the 

 number of children. But this hope is in some degree illusory, 

 because what frequently happens is merely that the distribu- 



