THE CONQUEST OF DISEASE 



bit, dog, or cat in a physiologic laboratory in 

 this country." Twenty-five years ago Profes- 

 sor Gerald Yeo estimated that in one hundred 

 experiments seventy-five were absolutely pain- 

 less, twenty as painful as vaccination, four as 

 painful as the healing of a wound, and one as 

 painful as a surgical operation. At the present 

 time not more than one experiment in one 

 hundred thousand is actually painful. 



