SEX-INCIDENCE IN ABORTIONS. 189 



influence it at the time of conception; that is to say, they do not have any sex- 

 determining effect, but by their influence upon intrauterine mortality they change 

 only the sex-ratio of the living-born. The well-known fact that the secondary 

 sex-ratio among Jews is relatively high is explained by Diising on the ground of 

 incest, blood marriages being of frequent occurrence in that race. Schultze (1903), 

 on the other hand, concluded that inbreeding has no effect upon sex determination 

 and the same conclusion was reached by King (1918). Busing, in his conclusions, 

 failed to make a distinction between the sex-ratio at birth and that at conception; 

 the latter is probably not different in Jews from what it is in other white races, 

 but changes less by reason of the relatively fewer abortions and still-births among 

 Jews, resulting in a higher secondary sex-ratio. The relative infrequency of abor- 

 tions among Jews has been shown, for instance, by Auerbach. One finds frequently 

 the assumption that the negro produces fewer sons than other races another 

 conclusion drawn from statistics of the new-born alone. Nichols pointed out that 

 in the Bistrict of Columbia still-births and abortions among the colored popula- 

 tion amount to 13.8 per cent of the living-born, whereas in the white it is only 6.5 

 per cent. This difference is responsible for the different secondary sex-ratios of 

 the two races (103.1 in negroes and 106.2 in whites). Punnett (1903) and others 

 have shown that the births among classes of lower social status present a lower 

 sex-ratio than those of the rich. The explanation lies again in the fact that the 

 greater frequency of abortions among women of the working classes, who can spare 

 themselves less during pregnancy and in whom pregnancies occur in more rapid 

 succession, 1 results in a corresponding reduction in the sex-ratio, which probably 

 was originally equal in the two classes. In addition, this greater reduction of the 

 primary sex-ratio in the poorer classes is due to their higher percentage of still- 

 births. According to Conrad in Halle, among laborers it was 5 per cent, while 

 among the upper classes it was only 2.1 per cent; and according to Verrijn Stuart 

 (1901), in Holland, among the poor, it was 3.16 per cent and among the rich 2.5 

 per cent of all births. 



A further example illustrating how the primary sex-ratio was erroneously 

 thought to be influenced is shown in its difference in legitimate and illegitimate 

 children. Heape (1909) states that the sex-ratio of legitimate births among the 

 white population of Cuba is 109.0, still-births included; that of the illegitimate 

 only 105.95. There is even a greater difference among negroes, the sex-ratio being 

 97.91 for illegitimate children and 107.73 for legitimate ones. Heape immediately 

 draws the conclusion that illegitimate unions result more often in the conception 

 of females than do legitimate ones. According to Busing, the sex-ratio of legitimate 

 births in Prussia, between the years 1875 and 1887, was 106.37; that of illegitimate 

 only 105.54. The still-births in legitimate unions amounted to 3.91 per cent, in 

 illegitimate ones to 5.32 per cent. A corresponding difference was demonstrated 

 by Bertillon (1896) in the frequency of legitimate and illegitimate abortions. The 

 greater mortality of illegitimate fetuses reduced the sex-ratio to a greater degree. 

 The rule that the sex-ratio is greater in legitimate than in illegitimate births is 



1 According to Diising (1884), the longer the intervals between births the higher is the sex-ratio. 



