' But, as soon as the attempt is made to think out the process in detail, we recognise 

 that here, too, we know nothing thoroughly, and that it would be uncommonly easy for 

 any one who wished to assign the processes of natural selection altogether to the realm 

 of phantasy to emphasise this view : for it is really very difficult to imagine this process 

 of natural selection in its details ; and to this day it is impossible to demonstrate it in 

 any one point.' 



The All-sufficiency of Natural Selection, by Professor Aug. Weismann, 

 Contemporary Revie-LV, September 1893, p. 322. 



