PREPONDERANCE OF MALE BIRTHS 7 



in Europe generally. For our present purpose it will be convenient to 

 express the excess in a different form from this. The result just cited 

 may be expressed by saying that, out of 2052 births, 1052 are males 

 and 1000 females. We may also say that 51.3 per cent are males and 

 48.7 per cent are females. Altogether, it seems to the writer that the 

 best expression for the sexes is the excess of male over female in 100 

 births. Since Mulhall's conclusion implies that in 100 births 51.3 per 

 cent are males and 48.7 per cent are females, the number expressing the 

 excess would be 2.6 per cent. The excess thus expressed is represented 

 by the symbol E' in . That is, we put E = the excess of male over 

 female births in a total of 100 births. 



The slight variations in this excess found in different countries are no 

 greater than may be the result of accident. Although its value is so 

 nearly the same for different countries, there are still some circumstances 

 to be considered in connection with this definition. The most important 

 of these is that it is decidedly larger when still-births are included. In 

 France the male excess of such births is between 4 and 5 per cent of the 

 whole number, a proportion which is probably substantially the same in 

 most European countries. If we desire E m to express the physiological 

 probability of the production of a male child, still-births should be 

 included. We should then have, in France, 



E m = 2.93. 



Although this expresses the proper physiological probability of the pro- 

 duction of male offspring, it will better conduce to our present operations 

 to consider only living births. For these we may take, as a normal 

 ratio, Mulhall's value, which will give 



E m --~-^ 

 From the statistics of Massachusetts the ratios are found to be: 



Living children, E m 2.8 All births, E m -= 3.3 



It appears, therefore, that there is no material difference on the two 

 sides of the Atlantic. 



3. IS THE RATIO OF MALE TO FEMALE BIRTHS THE SAME IN 



ALL RACES? 



So far as the author is aware the only races besides the Semitic for 

 which we have statistical data on which to base a conclusion are the 

 Mongolian race of Japan and the negro race in America. In the latter 

 we have only a limited registration of births, but sufficient to at least 

 point to a conclusion. The census of 1900 gives a registration record, 

 and a total record of births of children of the colored race as follows : 



