74 EVOLUTION 



CHARACTERISTIC FEATURES OF LIVING 

 CREATURES. The chemists tell us that the 

 physical basis of life always includes proteids 

 and similar highly complex substances, and 

 that the process of living involves an intricate 

 series of combustions and fermentations and 

 reconstructions, many of which can be 

 imitated outside the body altogether and 

 expressed in chemical formulae. On the other 

 hand we cannot give a chemical description 

 of any complete vital function, or of any 

 activity of the living creature as a whole 

 and unless, as the Germans say, we throw 

 away the baby with the bath, we cannot 

 ignore the most salient fact, that all the 

 manifold chemical processes are correlated 

 and controlled in a unified behaviour, in a 

 purposive agency. Even the amoeba is no 

 fool. 



The physicists tell us that the living creature 

 resembles some wonderful kind of engine; it 

 is a material system adapted to transform 

 matter and energy; and it illustrates in its 

 living a number of well-known physical pheno- 

 mena, of surface-tension, of diffusion, of 

 elasticity, of hydrostatics, of thermodynamics, 

 of electricity, and so on. At the same time 

 it has to be admitted that not even the 

 simplest vital activity, such as the passage 



