THE CANNIBAL IN EVOLUTION 163 



the changes were the result of stress of circumstance rather 

 than of instincts, however beautiful, which in all primitive 

 peoples tend to exert less and less power as the offspring 

 become able to take care of themselves. In conditions, 

 which even for the partially protected female were such 

 as must have employed all her energy to live, they would 

 have had little force. 



Although the explanation of the past by what occurs 

 now is sound in all sciences, such an instrument of discovery, 

 when it uses not permanent physical causes, like those 

 seen in geology, but evolved and evolving multiform factors 

 such as the instincts, needs some caution. While the 

 purely self-regarding and brutal instincts still seen in 

 many must even so be regarded as modified favourably 

 during social evolution, it may be assumed that the more 

 altruistic were in their origin less worthy of admiration 

 than they seem now. It is therefore more probable that 

 outside stress, rather than maternally introduced modi- 

 fications, conditioned the changes by which the sons were 

 permitted to stay in some sort of growing communion 

 with their parents, although avoidance was still strict, and 

 exogamy, or marriage by capture, from other nascent 

 groups or tribes, absolutely obligatory. 



With the existence of families in such proximity as 

 permitted wife capture it follows that, owing to the very 

 custom of capture, some kind of relationship should have 

 grown up. Even if the capture of wives were associated 

 at other times with the capture of prisoners, or carrying off 

 the dead for food, there would assuredly be intervals of 

 peace and comparative amity in seasons of plentiful game. 

 Although such friendly relations must have been slight 

 they would certainly be stronger than those with other 

 and remoter groups with whom no intermarriage was 



