286 C. G. CAMPBELL 



of mothers, our population promises in time to become largely dependent 

 for its survival upon other mammals that are more reliable in their lactation. 

 This might not seem to some a very serious threat to human survival, but 

 before it were dismissed as inconsequent, its corrolary biological significance 

 and its nutritional and constitutional effects upon infant development 

 would need fully to be explored. 



To determine the exact causes for the increase in unfavorable conditions 

 of reproduction that we have noted would require a most painstaking and 

 exhaustive examination, but the attendant circumstances cannot but come 

 under suspicion. Women bear their children at a later age than formerly, 

 and the average number of children that a woman bears is fewer. Women 

 have changed considerably in their mode of life. Many of them perform 

 much lighter domestic duties, there is a general tendency to minimize such 

 duties, and often to attach much less importance to them than to sedentary 

 occupations external to the home. Indeed many women have averted 

 their attention from tasks that were formerly regarded as germane to them, 

 and turned to interests, to careers, to recreations, and even to dissipations, 

 that were formerly only affected by men. The cogent bearing of these 

 circumstances might be denied by many; but such changes in the mode of 

 life of women must have inevitable physical effects, which may be already 

 asserting themselves. 



Equally great weight might be given to the fact that biological nature 

 rigidly cuts off weak mothers and eliminates them from the race, whereas 

 civilized man does his best to preserve them and often succeeds. This 

 is not advanced as an argument against such efforts, but it is only too ob- 

 vious that it results in lowering the general reproductive ability of the 

 female element of a population. This in itself would constitute a grave 

 racial problem even if medical science had been able fully to compensate 

 this deterioration. Nor does it seem that the gravity of the problem can 

 decrease as long as it is attacked only by the present methods. Medical 

 science achieves its results only through supplementing the processes of 

 biological nature, and these results cannot exceed that for which individuals 

 have the inherent biological capacity. If the biological capacity of women 

 for reproduction and to resist the physical menaces to that crisis is further 

 reduced, medical science will not be able to overcome and compensate this 

 deficiency. 



Turning to general physical factors of racial survival and improvement, 

 the broadest evidence of the physical fitness of individuals for survival is in 

 longevity. Individuals who tend to live longest will be those who have the 

 soundest organs and who are most immune or most resistant to intercurrent 



