6 THE MECHANISTIC THEORY OF LIFE 



facts, therefore, biology can apparently be 

 nothing but applied physics and chemistry. 

 When we come to matters of detail it ap 

 pears that biology does nothing, and can do 

 nothing, but ask physical and chemical 

 questions, and obtain physical and chemical 

 answers, in so far as the answers are more 

 than partial answers. In tracing, say, the 

 development of an organism, or investigating 

 the process of secretion, we, of course, obtain, 

 in the present state of knowledge, only 

 partial answers. We may not be able to 

 give a complete statement in physical and 

 chemical terms of the processes of develop 

 ment or of secretion ; but it remains true, 

 nevertheless, that the facts we are ascertain 

 ing are apparently nothing but physical and 

 chemical facts, however imperfectly defined. 

 Beyond these facts all is more or less empty 

 speculation, which scientific men would pro 

 bably do well to avoid. 



For further support the mechanistic theory 

 can appeal to the actual history of biology, 

 and particularly of physiology. Apart from 

 the constant controversies (to which reference 

 will be made shortly) between mechanists 



