320 PRINCIPLES OF STOCK-BREEDING. 



the proportion of males in births the greater the fe- 

 cundity." ' 



These generalizations appear to hare been made 

 without sufficient evidence, and the statistics relied 

 upon in support of them are susceptible, in many in- 

 stances, of a different interpretation. 



We have already seen that depressing influences, 

 in many cases, are favorable to fecundity; and the 

 statistics collected by Dr. H. B. Baker seem to show 

 that "causes tending to increase the birth-rate tend 

 also to increase the proportion of female offspring, 

 this being equivalent to decreasing the proportion of 

 males." 2 



Dr. Emerson, in the paper referred to, has appar- 

 ently shown that the cholera in 1832, in Philadelphia 

 and in Paris, diminished the proportion of male births 

 for the year 1833, and that this excess is most marked 

 in the period of the year nine months after its " most 

 fatal ravages." * 



A reexamination of the statistics used by Dr. 

 Emerson has been made by Dr. Baker, who shows 

 that the birth-rate was also increased in this epidemic ; 

 and he adds evidence of a similar character from the 

 Registrar-General's report, in regard to the influence 

 of cholera in England in 1854. 4 



The statistics of 1,427,719 births in New York 

 City, Philadelphia, Providence, Yermont, Massachu- 



1 Philadelphia Medical Times, December, 1873, p. 193. 



2 Michigan "Fourth Registration Report," 1870, p. 78; Michigan 

 " Fifth Registration Report," 1871, p. 103. 



8 American Journal of the Medical Society, July, 1848, pp. 78-85. 

 4 Michigan "Fifth Registration Report," 1871, pp. 96-99. 



