26 HEREDITY AND EUGENICS 



Differences in reactions to serums and to various 

 diseases, as well as other evidence, indicates the 

 existence of corresponding chemical and constitutional 

 differences between individuals. The inheritance of 

 such differences is now commonly recognised. Only 

 a few years ago, in the Law Courts, the disposal of a 

 large estate turned upon a peculiar conformation 

 of the ear occurring in the father and the supposed 

 son.* 



A considerable bod}^ of detailed evidence concerning 

 heredity in man has accumulated in recent years. 

 It is not my purpose to attempt anything like a 

 complete citation of this work, but it may be of 

 interest to enumerate some of the studies which have 

 been made on this subject; for our knowledge of 

 the inheritance both of normal and abnormal traits 

 in man must always form the chief basis for eugenic 

 action. 



1919) has shown that in crosses between the North African and 

 South African ostrich the bald spot of the former behaves as a 

 simple dominant character not sex-linked. In the chicks the 

 head is covered with a bristly down, but in the North African 

 birds this gradually falls out during the first few months and is 

 not replaced by feathers. 



* On the other hand, a case is cited (Jenks, 1916), with some 

 evidence of authenticity, in which a girl of Swedish ancestry, 

 whose ancestors of both sexes had been accustomed for many 

 generations to wear earrings, was born with a hole in the proper 

 position in each ear-lobe. That such cases of inheritance of a 

 mutilation are admittedly rare does not necessarily prove that 

 they are non-existent. The fact that (Windle, 1891) a fissure 

 sometimes occurs in the sulcus intertragicus of the ear, as an 

 arrest of development, scarcely seems an adequate explanation 

 of the above case; but in an instance cited by Windle where the 

 mother tore the lobule of her left ear when eight years old, and 

 afterwards had eight children, one of whom, a boy, had cleft lobule 

 of the left ear, there is obviously no inheritance involved. 



