122 THE LAW OF BIRTHS AND DEATHS 



ously wider than the pelvis of the average savage woman. 

 What are needed in this connection are systematic observa- 

 tions extending over a number of generations. 



Such a number of authorities have confirmed the fact 

 of the steady decline of the birthrate from the poorest 

 to the richest classes, and such a mass of statistics have 

 been gathered in support that it seems unnecessary to 

 go in for an extensive discussion of this aspect of the 

 problem. The following table by Dr. Bertillon showing 

 the number of legitimate births per 1,000 women in Paris 

 and Berlin is typical : 



Nothing could be more striking than the gradual reduc- 

 tion of the degree of fertility as the population grows 

 richer. It would probably be possible to estimate the 

 degree of fertility of any given section of a community 

 by calculating its average income. No really satisfactory 

 explanation of this phenomenon has ever been put forward 

 under the accepted hypothesis. For why should a man 

 with, say, 50 a year limit his family to perhaps 

 five, and the man with 100 a year limit his family 

 to four, and the man with 200 limit his family 

 to three, and so on until we reach the vanishing point 

 among the very rich, who in a vast proportion of cases 



