EVOLUTION OF PHYSICAL CHAKACTEES 375 



holds good if we consider any primitive race in its normal sur- 

 roundings. 



That this is so is clear if we glance at the chief causes of 

 elimination. The heavy child mortality recorded of all these 

 races is put down to neglect and exposure ; it must on the whole 

 result in the elimination of the physically weak. Such customs 

 as the bathing of new-born babies in cold water seem designed 

 to ensure this result. Among the adults who on the whole are 

 but little protected against climate there must always be a certain 

 tendency towards the elimination of those less able to withstand 

 the relatively harder seasons. There are also many factors 

 making for the cutting-off of the malformed and the congenitally 

 deficient. Among those races which normally practise infanticide, 

 deformed children are always killed, and among those races, such 

 as the Bantu races of Africa, who never regularly practise 

 infanticide as a custom, abnormal children are nearly always 

 done away with. Similarly the destruction of witches tends 

 towards the same end though they are more often marked by 

 mental than by physical peculiarities. Again the fact that 

 abortion and infanticide are practised to a greater degree among 

 the less fortunate and the lower social classes of the races in the 

 second group has the same result, as in general the stronger and 

 more successful members of the race are those who do not need to 

 practise these customs to the same extent. Finally, the general 

 conditions of life among these races — more particularly among 

 the races of the first group — is such as to bring about a continual 

 elimination of the less physically fit. Speaking of the Seri Indians 

 McGee remarks upon the ' elimination of the weak and helpless ', 

 and says further that * a parallel eliminative process is common 

 among American aborigines ; the wandering bands frequently 

 undergo hard marches under the leadership of athletic warriors 

 with whom all are expected to keep pace, which leads both to 

 the desertion of the aged and the feeble '. He calls it ' a merciless 

 mechanism for improving the fit and eliminating the unfit '.^ 



As remarked above, the effect of polygamy must be to intensify 

 the action of selection. In this particular case the general result 

 of polygamy must be to preserve the average features of the 

 race ; for it will be, so to speak, the all-round man, the man best 

 adapted to the climate, to the peculiar conditions of life and so 



^ McGee, loc. cit., p. 157. 



