SOME POSSIBLE CRITICISMS ANTICIPATED 161 



the degree of fertility to suit the deathrate, then the 

 decline " cannot possibly be a source of anxiety." Un- 

 fortunately, this optimism is unjustified, and is the result 

 of a failure to grasp clearly the essential factors of the 

 problem. There is a limit to the fall in the deathrate. 

 Even when the deathrate is reduced to the lowest possible 

 level, people will continue to die of old age. Now, the 

 author of the phrase quoted above seems to have been 

 under the impression that when the deathrate ceases to 

 fall, the birthrate will cease to fall also. There is no 

 justification for such a belief. 



The theory set forth in this work is not that the fall 

 in the birthrate is caused by the fall in the deathrate, 

 but that it is produced by the same combination of cause* 

 which produces a falling deathrate. Thus, if Mr. Brown 

 dies of fever, consumption, or other ailments, this will in no 

 way affect the fertility of Mrs. Jones. But the combina- 

 tion of causes or the environment which produces a con- 

 siderable number of deaths from these ailments may 

 very powerfully affect Mrs. Jones's fertility. And when 

 the deathrate is reduced to its lowest possible term, the 

 environment will not cease to affect the birthrate. An 

 accentuation of the causes which have produced a low 

 birthrate in the past will reduce it still further. For no 

 limit can be set to the decline of fertility short of absolute 

 barrenness. That is why the problem of the declining 

 birthrate must be grappled with, lest it result in ultimate 

 depopulation, or the replacement of our population by 

 lower races, as happened in Ancient Rome and Greece. 



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