48 ESSAYS OF A BIOLOGIST 



types : but the full potentialities of the mammal 

 (excluding man) were not realized until well over 

 half of the Tertiary period had elapsed, and man 

 was being prepared in the womb of circumstance. 

 The Pliocene sees the triumph of the perfected types 

 of mammal : the preceding Miocene, broadly speaking, 

 sees the first rise of these new types, while the Eocene 

 and Oligocene show us a rapid rise and as rapid extinc- 

 tion of variation upon variation on the original theme. ^ 

 With man, however, only the beginnings of a 

 similar process have as yet come to pass. 



Further, we must distinguish clearly between the 

 different ways in which progress may be operative 

 in man. In the first place it can appear, as we have 

 just pointed out, in the organizationof the communities 

 to which he belongs and on which natural selection 

 seems mainly to act. Secondly, it can appear as a 

 raising of the average of certain qualities among the 

 individuals composing those communities. And thirdly, 

 it can appear as a raising of the upper /^W of attainment 

 in those qualities, in the appearance of individuals 

 biologically higher than any that have previously existed. 



This last point may be first dealt with. It has 

 often been urged as an argument against the doctrine 

 of progress that we can trace no advance in the cap- 

 abilities of the individual man throughout history, 

 and it has even been asserted that no such advance 

 has occurred during pre-history. To this latter 

 1 See Woodward, '98 ; Osborn, '10. 



