NATURAL SELECTION IN MAN 201 



the defective members of the race and if it does not eliminate 

 them directly, it causes or rather augments the death rate of their 

 progeny and hence works toward the extirpation of their breed. 



From the standpoint of eugenics the infant mortality that 

 results from inherent incompetence or moral depravity has its 

 obvious advantages. If stocks such as the Jukes, Kallikaks and 

 Tribe of Ishmael had had an infant mortality even higher than it 

 was there would be few who would regret the fact. It would have 

 been much better had these degenerates never been born. But 

 having been brought into the world perhaps the next best thing 

 would have been for them to have died young. 



By way of summary the kinds of infant mortality we have 

 distinguished may be expressed as follows: 



1. Non-selective elimination. This is of no racial value and not 

 only masks the workings of natural selection, but interferes with the 

 stringency of its action. 



2. Selective elimination of non-hereditary characters. We might 

 consider this a racially impotent form of natural selection. 



3. Selective elimination of characters of value only during infancy. 

 Racial effect not beneficial beyond rendering infancy more hardy. 



4. Selective elimination of infantile weakness or defect which would 

 produce diminished vigor in later life. 



5. Selective elimination of infants not in themselves weak or imper- 

 fect, but who would develop into socially undesirable persons. They 

 are eliminated in greater numbers because of the incompetence of 

 their parents. 



The last two forms of selection are strongly working in the 

 direction of racial advance. 



The doctrine that the human species may be in any way im- 

 proved through the selective elimination of infants has been 

 opposed on the ground that whatever agencies cause babies to die 

 would also involve more or less permanent injury upon the sur- 

 vivors. In commenting on those writers who commend a high 

 infant death rate on account of its selective value. Dr. Saleeby 

 remarks: "But waiving here the observation that 'natural selec- 



