SEX. 323 



same sex, and in the remaining 2,159 only, of differ- 

 ent sexes." * 



Of 457 cases of twins, collected by Churchill, both 

 children were males in 131 cases, both females in 146 

 cases, and one male and one female in 179 cases. 2 



Of 56 cases of triplets, there were 3 boys in 18 

 cases, 3 girls in 14 cases, 2 boys and 1 girl in 11 cases, 

 1 boy and 2 girls in 9 cases, and in 4 cases the sex is 

 not stated. 8 



Thirteen cases are reported of 4 children at one 

 birth, of which there were 4 boys in 3 cases, 4 girls 

 in 2 cases, 3 boys and 1 girl in 3 cases, 2 boys and 2 

 girls in 1 case, 1 boy and 3 girls in 2 cases, and in two 

 cases the sex is not stated. 4 



In Michigan there were 389 cases of twins reported 

 in 1870, and 298 cases in 1871, the proportion of males 

 to 100 females being 107.14 in 1870, and 112.85 in 

 1871. 6 



It has generally been supposed that the production 

 of twins was an indication of unusual f ecundity ; but 

 Dr. Duncan, who is a high authority on this subject, 

 remarks that " the variation of the frequency of twin- 

 births in different countries is so great as to remove 

 all probability from the notion or belief that the 

 greater or less frequency of twins shows greater or 

 less general fertility." 



1 "Insurance Cyclopaedia," vol. L, p. 318. 



a " Theory and Practice of Midwifery," p. 402. 



3 "Insurance Cyclopaedia," vol i., p. 318 ; vol. in., p. 200. 



4 Ibid., vol. iii., pp. 200, 201. 



6 Michigan "Fifth Registration Report," 1871, pp. 93, 94. 

 6 Duncan on " Fecundity ; " quoted in " Insurance Cyclopaedia," vol. 

 iii., p. 195. 



