Abstract
References
1.
Darwin
, “Animals and Plants under Domestication ,” ii , 319 .
2.GIBBS , Dental Cosmos , 1916 , lviii , 352 .
3.
Cerny
, Dental Cosmos , 1924 , lvi , 583 .
4.
Harris
, Proc. Roy. Soc. Med. (Child. Sect.) , 1927 .
5.
Cockayne
, ibid. , 1920–21 , xiv , 17 .
6.
Pitts
, ibid. , 1923 , xvi , 45 .
7.
Smith
, Arch. Dis. Childhood , 1929 , iv , 215 .