NOMADISM, WITH SPECIAL REFERENCE TO HEREDITY. 23 



in the population, the large proportion of nomadic females in tables 4 

 and 5 speaks strongly for the view that there is a single sex-linked deter- 

 miner that makes for domesticity, and that only where it is absent 

 from the germ-cells of both parents will the daughters be nomadic. 



The large number of nomadic sons in tables 4 and 5, where the father 

 is nomadic, would seem to speak against the hypothesis that the father's 

 gerrn-plasm does not influence the nomadism of the sons. But it must 

 be remembered that our tables comprise only fraternities of offspring 

 who show some case of nomadism. By reference to our family histories 

 numerous cases will, however, be found where a nomadic father has 

 no nomadic sons (e. g., families 3, 25, 29, 30 (4 children), 34, 36, 42, 61). 

 But there is, I think, no case of a nomadic mother of more than 2 

 children of whom none is nomadic. Moreover, the great frequency of 

 nomadic fathers of nomadic sons (not called for by the hypothesis) is 

 quite certainly due to the circumstance that nomadic men are apt to 

 marry women who either are nomadic themselves or belong to nomadic 

 stock. The case of Borrow, who took up with the itinerant Isopel 

 (Borrow, 185 1), illustrates this tendency. 



Alternative hypotheses to the one proposed above must be considered. 

 Nomadism may be an essentially male characteristic and one which, 

 like the beard of man, depends upon hormones elaborated by the male 

 germ-glands. Against this hypothesis is the fact that nomadism is by 

 no means confined, to the male sex; in certain matings daughters as well 

 as sons are nomadic. The distribution of the nomadic trait among the 

 offspring is, then, a function of a particular mating. 



The hypothesis has been urged that nomadism is less common among 

 women than among men because it is less feasible for women to live a 

 nomadic life. But no one who carefully examines the family histories 

 here given, especially Nos. 53, 55, 46, 47, can seriously maintain this 

 view. The fact that among gypsies, for example, women enter into the 

 life with the same inevitableness as men speaks against the hypothesis. 

 On the other hand, the frequency of nomadic women among gypsies is 

 easily explained by a consideration of their pedigrees. One rinds on 

 examination of such pedigrees as are published in the Journal of the 

 Gipsy Lore Society that nomadic men and women commonly marry each 

 other and, as our hypothesis leads us to expect, all the offspring are 

 nomadic. Thus all the evidence supports the hypothesis that the 

 nomadic impulse depends upon the absence of a simple sex -linked gene 

 that "determines" domesticity. 



