THE CAVENDISH LECTURE 



17 



fertility of the fitter stocks and we have the state of affairs — the 

 very grave state of affairs — which we of to-day are called upon to 

 meet. 



Now you will say, and rightly say, that each stage of this argu- 

 ment needs to be supported by very solid facts. Well, as far as 



033BSAti HEALTH. 



T 



150 125 100 

 '• ROBnsT 



50 E5 -85 -50 -T5 -100 -125 -150 -175 

 PATETIR 



"iG. 3. — Diagram illustrating fall in health of son with fall in health of 

 father. Note anomalous position of sons of delicate fathers. In these 

 diagrams 100 units of health correspond to the normally healthy group. 



is consistent with the time available let me give you illustrations 

 of what I mean. 



In the first place, I hope you will agree with me when I say 

 that the general death-rate is selective. Secondly, the progress 

 of medical and sanitary science has altered the stringency of selec- 



