THE CAVENDISH LECTURE 3 



influences of special environments, alcohol, syphilis, tuberculosis, 

 insanity, feeble-mindedness, all racial defects known or asserted to 

 influence future generations, fall at once into the category of 

 medical experience, even if ability, genius, physique, and crafts- 

 manship belong less markedly within its sphere. 



Who are the men who, alone in the present state of our develop- 

 ment in this country, can provide adequate data as to the influence 

 of occupation, environment, parental history, on the racial quali- 

 ties of future generations? Why, in the first place they are the 

 local medical officers of health, who, directly and through their 

 district visitors, are recording home environment, parental occupa- 

 tion, and infantile and child health and mortality. And in the 

 second place they are the school medical officers, who are annually 

 examining thousands of children and scheduling their character- 

 istics. And in the third place they will shortly be the medical 

 officers of the National Insurance scheme, who will have material 

 at their disposal of even wider importance and of more interesting 

 scope. 



To the outsider, like myself, it appears as if a sharp dividing 

 line were being at present drawn right across the medical pro- 

 fession. I do not suggest that men will not at first pass from one 

 division to the other, but the interests of the two divisions will be 

 largely distinct, the tastes of the men who follow them will be 

 widely different, and ultimately the training will be markedly 

 differentiated. The one class of men will be in public service, 

 they will be studying and recording humanity in the mass — the 

 normal and the pathological, side by side — their objects will be 

 to enforce medico-social legislation, and to provide data from 

 which proposals as to further legislation can be judged. The 

 limits to the public health service seem for the time beyond our 

 ken ; we are only at the very beginning of the movement, and its 

 possibilities are enormous, and in one sense or another every 

 man in that service is concerned with what makes for the racial 

 efficiency of future generations — he must nolens volens become a 

 eugenist. 



Pray understand me. I am using the term " eugenist " in no 

 narrow sense. I do not signify by it membership of any pro- 

 pagandist body — such societies often do more harm than good to 

 the cause we have at heart. 1 do not understand by eugenist 

 one who desires to segregate the mentally defective or prohibit 

 the epileptic from parentage, although I might sympathise with 



