354 HEREDITY AND SELECTION IN SOCIOLOGY 



is doomed to extermination. As typical of the physiological 

 superiority attained under such conditions, we may mention the 

 case of the Red Indian squaw who, when about to give birth to 

 a child, while the tribe was on the march, simply concealed her- 

 self in the brushwood until her delivery was accomplished ; after 

 which, with the new-bom infant on her shoulder, she followed 

 up the tribe, which did not delay its march. Many women must 

 necessarily have succumbed under these conditions ; but those 

 who survived such a test must have been the mothers of strong 

 and healthy progeny. 



In the first part of this book we have endeavoured to insist 

 particularly on the fact that it is selection which is responsible 

 for all the transformations and modifications effected in the organic 

 world. The factors of this selection we saw to be variability, 

 heredity, the survival of the fittest, and overfertility. It is 

 this latter factor which is the chief source of aU the progress 

 accomplished. That the conditions of organic existence are 

 such that a greater number of individuals are always born 

 than can survive, gives us the key to the problem of organic 

 progress. It is only on condition that reproduction exceed the 

 possibilities of biological existence that competition for space 

 and food can take place ; for if there were sufficient space and 

 food for all the progeny of a couple, there would be no necessity 

 for competition — each species, and each individual within a 

 species, would find conditions favourable to its maintenance. 

 If this were the case, transformations might take place, if the 

 somatic modifications acquired during the lifetime of the 

 individuals were transmitted by heredity ; but, as we have 

 seen, such transmission of somatic characters is impossible ; 

 and therefore transformations could only be effected by 

 the direct influence of external factors such as climate and 

 food. But even in this case there would be no progress ; 

 the extraordinary evolution which has led from the Amcfiba 

 to Man, and which has produced so many forms of life 



