PROLIFEROUS CELLS AND NEOPLASIA 275 



tissues become exhausted, the more highly differentiated cells 

 tend to become structurally simpler, revert, that is to say, to a 

 simpler type, and, with this simplification of structure accom- 

 panying atrophy, there may be, I would suggest, along the lines 

 already laid down, a greater liability for those cells to assume 

 proliferative powers. 



