4 THE MECHANISTIC THEORY OF -LIFE 



of energy, generated from and immediately 

 passing back into other forms. Cut off the 

 oxygen supply to the brain, and conscious 

 ness ceases within a few seconds. It makes 

 no difference to the energy balance of the 

 body whether an animal is conscious or not ; 

 and it seems simplest, in the present state of 

 knowledge, to treat consciousness as an ac 

 companiment, not altering in any way the 

 physical and chemical changes which it 

 accompanies, of certain intra-protoplasmic 

 changes. 



The mechanistic theory may be supported 

 by another set of considerations, which appeal 

 very strongly to many scientific investigators. 

 In all biological investigations we are investi 

 gating either structure or activity ; and when 

 we come to details we find that the struc 

 ture is physical and chemical structure, and 

 the activity physical and chemical activity. 

 Hence biology can be nothing but the physics 

 and chemistry of organisms. 



This argument may be illustrated in almost 

 infinite detail. Let us suppose that we are 

 engaged in anatomical investigation. With 

 the scalpel, microtome, microscope, fixing 



