ORGANIC EVOLUTION — PHYSICAL 41 



Every kind of cell performs one function specially well 

 and the others not so well, or not at all. The result 

 of this cell-specialization and differentiation is, like the 

 results of increased specialization and differentiation in 

 the labours of civilized men, increased efficiency of the 

 organism as a whole, and the result of the increased 

 efficiency is, of course, an increased average rate of 

 survival. 



