PHYSICAL CHARACTERS IN MAN 71 



to the tail. Wild white cattle from Thessah', etc., 

 were also known to the Greeks and Romans, and in 

 ItRly a white breed, in which the calves are yellowish, 

 continues down to the present time. 



Three types of albino horses have recently been 

 described (Wriedt, 191 8) in two Norwegian breeds. 

 The heterozygous condition is intermediate in these 

 horses, and albinism appears to behave nearly the 

 same as in guinea-pigs. 



Civilisation has often been credited with the pro- 

 duction of the numerous congenital deformities that 

 appear in man. But various studies, such as that of 

 Stannus (i 914) on the Bantus of Nyasaland, show that 

 the same abnormalities continue to appear, probably 

 with equal frequency, in native races, even though 

 the more marked of them are ruthlessly eliminated 

 by infanticide. It is evident that the conditions of 

 civilisation tend rather to preserve than to originate 

 abnormalities, and that natural selection in native 

 races, as in wild animals, combined with parental 

 selection, tends to eliminate individuals possessing 

 characters which place them at a disadvantage in 

 the struggle for existence. 



A short account is published (Thadani, 1921) of a 

 Hindu Amil community in India, in which a toothless 

 type of man occurs. The men are not only toothless, 

 but bald-headed and extremely sensitive to heat. 

 The evidence, so far as it goes, indicates that the 

 character is sex-hnked. Anodont females are not at 

 present known, but if daughters of a toothless father 

 are married to a normal man, their male children are 

 toothless (Bhudas). 



Left-handedness. 



Another innocuous feature whose inheritance is 

 well known is left-handedness, which the results of 

 Jordan (191 1) and of Hurst {1912) indicate is inherited 



