No. 485] THE DETERMINATION OF SEX 



309 



Table III. 





(Taken from Ses 



sional I aj)ti.s ( 



. t le ouse o 



.OK s) 



Year 



Total Births 



Mal,.< 







1899 



928646 



4731 72 



.];,;, 4 74 



!();>(, 



1898 



923265 



468920 





1032 



1897 



921693 



469180 



452513 



1037 



1896 



915331 



465660 



449671 



1035 



1895 



922291 



468886 



453405 



1034 



1894 



91457^ 



453016 



437273 



1036 













1892 



897957 



456622 



441335 



1034-5 



1891 



914157 



465660 



448497 



1038 



1890 



869937 



442070 



427867 



1033 





879868 



447172 



423696 



1033 



888 



885944 



451218 



434726 



1037 





10,864,950 



5,527,287 



5,336,663 



1036 



It wi 



11 be seen that the ratio for any 



one year does not differ by 





than four in one 



i thousand fror 



n the mean calculateti from 





than ten million 



births. As a 



further example, 



the sexual 





in Massachusetts, based upon li-^ 



,'ing births only, for the years 



1856 to 1875 inclusive 



'. is 1059. The 



• ratio for the yei 



ars 1876 to 



1896 inclusive, based upon a considerably greater number of births, 

 is 1053. The mean for the two periods is 1055. The sexual ratio 

 for the period in which the Civil War occurred differed by approxi- 

 mately one half of one per cent from the later period of peace, 

 and by less than one half of one per cent from the mean of the 

 two periods. If external conditions exerted any effect upon the 

 parents in such a way as to change the sex of tlie offspring, the 

 change due to such influences was not greater than one in two 

 hundred. 



Social, political and material conditions in i-aiglaml (iiuing ilie 

 for the two periods — KHIS to 10(10, and lO.'Kl to lOOO re-])ecti\ ely 



