Biology and Medicine 



469 



in groups around the tables of exhibits; they listen to the 

 stories of improvement as told by those who have been treated, 

 and return to their homes to report to their neighbors what 

 they have seen and heard. . . . The effect of these edu^a- 

 tional activities is seen mst of all in the transformation which 

 has been wrought in public sentiment. This change of senti- 

 ment shows itself in the co-operation of the press which is 

 now practically universal in all the States in the growing 

 co-operation of the physicians, of the educational agencies, 



THE RESULT OF HOOKWORM TREATMENT 

 (Left) A victim of hookworm. 

 (Eight) The same girl after treatment. 

 Courtesy of the Rockefeller Foundation. 



of the whole people ; it shows itself in an increasing support, 

 not only of this particular work, but of all public-health in- 

 terests." 16 



Probably in no field of medico-biological research have ani- 

 mals played a larger part than in the investigation of can- 

 cer. Rats and mice have been the principal subjects for 

 these experiments, because of the readiness with which can- 

 cerous and other growths can be transplanted in them, and 



18 "The Rockefeller Sanitary Commission," Second Annual Report, 

 pp. 17-22. 



