DECADENCE AND REVIVAL 31 



doubted fact that the biologists of the two 

 former countries have devoted their attention 

 much more largely to ontogenic questions, that 

 is, to matters relating to the life-histories of 

 living things, whilst English attention, thanks 

 no doubt to the stimulus given by Darwin, 

 has been more directed to pylogenetic in- 

 quiries, that is, to the consideration of rela- 

 tionships between different living things. 



It is also a curious point that physicists and 

 chemists are far more chary of agreeing to the 

 ohemico-physical explanation of life than are 

 biologists, and this fact is no doubt explained 

 by the greater knowledge of the limitations 

 and possibilities of their subjects which is pos- 

 sessed by chemists and by physicists as com- 

 pared with the acquaintance with those subjects 

 which falls to the share of most workers in 

 biology. 



Liebig in his day (1803-73) declared that the 

 opponents of Vitalism were mostly strangers 

 to the sciences which investigate physical and 

 chemical forces, and we shall yet encounter 

 more than one instance where biologists have 

 claimed from chemistry and physics positions 

 which chemists and physicists have been un- 

 willing to surrender to them. 



When mentioning Liebig, one cannot refrain 

 from thinking of another class to which he 



