Page:George Archdall Reid 1896 The present evolution of man.djvu/53

Rh 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.