THE INHERITANCE OF DURATION 183 



we point out this disagreement, and assert a doctrine which, in the present 

 sentiment of society, is bound to he impopular. We have no feelings of 

 antagonism towards the efforts which have been made in recent years to 

 save infant life, but we think that the probable consequences of such actions, 

 so far as past experience can indicate them, should be completely under- 

 stood. All attempts at the reduction of mortality of infancy and childhood 

 should be made in the full knowledge of the facts of heredity. Everybody 

 knows the extreme differences in constitutional fitness which exist in men 

 and women. Few intelligent people can be ignorant of the fact that this 

 constitutional fitness is inherited according to laws which are fairly 

 definitely known. At the same time marriage is just as prevalent among 

 those of weak stocks as among those of the vigorous, while the fertility 

 of the former is certainly not less than that of the latter. Thus a propor- 

 tion of the infants bom every year must inevitably belong to the class 

 referred to in the report as "weaklings," and, with Pearson's results before 

 us, we are quite convinced that true infantile mortality (as distinct from 

 the mortality due to accident, neglect, etc. — no small proportion of the 

 whole) finds most victims from among this class. Incidentally we would 

 here suggest that no investigation into the causes of infant and child 

 mortality is complete until particulars are gathered by the medical ofiBcers 

 of the constitutional tendencies and physical characters of the parents. 



Our work has led us to the conclusion that infant mortality does effect 

 a "weeding out" of the unfit; but, though we would give this conclusion 

 all due emphasis, we do not wish to assert that any effort, however small, 

 to the end of reducing this mortality is undesirable. Nobody would suggest 

 that the difference between the infant rates in Oxfordshire and Glamorgan- 

 shire (73 and 154 per 1,000 births respectively, in 1908) was wholly due 

 to the constitutional superiority of the inhabitants of the former county. 

 The "weeding-out" process is not uniform. In the mining districts of 

 South Wales, accident, negligence, ignorance and insanitary surroundings 

 account for much. By causing improvements under these heads it may 

 be possible to reduce the infant mortality of Glamorganshire by the sur- 

 vival of many who are not more unfit than are those who survive in 

 Oxfordshire, and the social instincts of the community insist that this 

 should be done. 



This work of Snow's aroused great interest, and soon 

 after it appearance was controverted, as it seems to me 

 quite unsuccessfully, by Brownlee, Saleeby and others. 



Happily the results of Pearson, Ploetz and Snow on 

 the selective death rate have recently been accorded a 

 confirmatioij and extension to still another group of 



