THE CAVENDISH LECTURE II 



Galton's definition, a true eugenist. I know from many talks 

 with medical officers of health that at least a moiety of the 

 problems before which they find themselves at a halt are precisely 

 the fundamental problems of eugenics. The alliance between this 

 branch of medicine and eugenics is in the essential nature of 

 things ; it is basal ; and no amount of surface differences, no 

 intensity of personal prejudices, can avail to screen it perma- 

 nently. 



Is it not after all this fundamental fact, the existence of this 

 alliance, which explains the invitation of your Council and my 

 presence here to-night ? So far it seems to me that those who 

 are really working at scientific inquiry in eugenics and those 

 belonging to an important section of the medical profession are 

 wholly at one in their aims. But there is undoubtedly a fly in the 

 amber, and if the alliance between eugenics and medicine, as a 

 whole, is to be a real one, we cannot for a moment overlook a 

 possible source of divergence between them. 



I belong to a school which still believes that Darwin taught us 

 the truth. I think it is rather the fashion nowadays to dismiss its 

 views, not by meeting its arguments, but by describing it as "mid- 

 Victorian." When in literature, science, and statemanship this 

 twentieth century has produced minds which out-top the " mid- 

 Victorians," then it will be time enough to reply to a mere nick- 

 name. Let me, even at the risk of talking about the familiar, 

 sketch for you the broad outlines of Darwin's theory of evolu- 

 tionary progress. The individual better fitted to its environment 

 lived longer than its fellows, had more offspring, and these, 

 inheriting its better fitness, raised the type of the race. The 

 environment against which the individual had to struggle here was 

 not only formed by the other members of its species, not only by 

 its physical surroundings, but by the germs of disease of all types. 

 According to Darwin — and some of us still believe him to be 

 right — the ascent of man, physical and mental, was brought about 

 by this survival of the fitter. Now, if you are going lo take 

 Darwinism as your theory of life and apply it to human problems, 

 you must not only believe it to be true, but you must set to, and 

 demonstrate that it actually applies. That task I endeavoured to 

 undertake after the late Lord Salisbury's famous attack on 

 Darwinism at the Oxford meeting of the British Association in 

 1894. It was not a light task, but it gave for many years the 

 raison d'etre of my statistical work. In the first place it was demon- 



