2 HEREDITY AND SOCIETY 



This universal recognition of the family as the true 

 social unit and of the ties of kinship as the most 

 powerful of binding forces is in effect a tacit recog- 

 nition of the part played by heredity in fashioning 

 human society. Were there to exist no correlation of 

 qualities between parents and children, brothers and 

 sisters, kinsmen and kinswomen, either in physical or 

 mental characteristics, the problem of forming coherent 

 societies and of creating and maintaining an environment 

 suitable for succeeding generations would be insoluble. 

 It is because persons belonging to the same race have 

 certain definite characters in common that they are 

 capable of thriving in the same conditions of climate, 

 in the same mental and moral atmosphere, of under- 

 taking the same class of labour, of resisting the same 

 diseases. Thus the human populations of the globe, 

 like the flora and fauna, have separated out into the 

 various species, inhabiting in comfort the different 

 geographical zones, and showing marked differences of 

 appearance, of capacities, of requirements. It is because 

 families who are united by ties of blood are in like 

 manner, but to a less marked degree, separated off from 

 their fellow-men, that it has been possible for the indi- 

 viduals of each race, as for animals, to differentiate 

 among themselves and to develop and extend the various 

 manifestations of those qualities inherent in the human 

 race which are essential to the increasing complexity of 

 modern civilization. In the same way the exigencies 

 of natural selection and of human need have divided 

 the qualities inherent in the equine race between the 

 hardihood of the Shetland pony, the strength of the 

 Clydesdale or Shire horse, and the speed and mettle of 



