268 



Mr Punnett, 

 Table V. 



These figures, then, give the proportional birth-rate in the three 

 groups, subject however to the following source of error. Since 

 the data are given in terms of infants under 1, and not of births, 

 and since the mortality is greater in the poorer district (i.e. greater 

 in A than in B, and in B than in O), it follows the birth-rate of 

 B is a trifle low as compared with G, and that of A slightly more 

 so. This, however, will not make much difference to the above 

 figures. Hence we may conclude that the greater the servant- 

 keeping capacity, the smaller becomes the birth-rate. It now 

 remains to examine : — 



(6) The influence of curtailment of the family. If the sexes 

 are not equally spread over families, but if one sex tends to 

 predominate over the other for the first few births, it is evident 

 that any factor which affects the birth-rate will indirectly influence 

 the proportion of the sexes. Thus if </" infants tend to make 

 their appearance in a family before $ infants it is evident that 

 any restriction of the family by artificial means will increase the 

 relative proportion of <fs, though the birth-rate will be di- 

 minished. Data for the consideration of this point were collected 

 from Burke's Peerage (1894). They comprise 721 families with 

 a total of 3046 children, of which 1618 were ^s and 1428 $s. 

 The size of the family varied from 1 to 16, and the succession 

 of the sexes is known in each case (vide Table VI). The relative 

 proportions of the sexes in the different parts of the family are 

 given in the subjoined table. The families considered are those 

 of the heads of houses. Consequently there is every reason to 

 suppose that no artificial restriction has been placed on the 

 number of the family. 



This table brings out very clearly the fact that the chances 

 are greatly in favour of the first child born of a marriage being 

 a £ (i.e. 140 to 100). The chances of the second child being a 

 male are also considerable (117 to 100). After this the chances 

 of a male child appearing diminish until the ninth and subsequent 

 births, when the chances of either sex are precisely equal. From 



