120 ORGANISM AND MECHANISM 



the stoker cease to stoke or if the draught of air be less- 

 ened, or in other ways. Similarly, the temperature of the 

 body in a t warm-blooded ' animal is automatically regu- 

 lated to a nicety so that, if it exceed the normal even by a 

 very little, we know that something is seriously wrong. But 

 there are great differences between the organism and the 

 furnace. Thus in the organism " the oxidation does not, 

 like ordinary chemical oxidation, increase or diminish in 

 proportion to the varying supply of oxygen brought to the 

 seat of oxidation, but is controlled by living cells ". 



We can picture a complicated series of mechanical opera- 

 tions with here and there an intelligent workman who is 

 essential because what is required is like very intricate 

 shunting a regulation, an adjustment, a co-ordination. So 

 is it with the organism. We can give a chemico-physical 

 account of isolated processes, but we cannot give a connected 

 description of the whole without postulating the interven- 

 tion of living cells. Not hypothetical agents, like Clerk- 

 Maxwell's " sorting demons," but observable living cells like 

 Amoebae. 



Let us take another illustration. When we strike a match 

 we can give a complete chemico-physical account of the later 

 phases of the process, apart, that is, from our own intention 

 and movement. When we draw back our finger from a hot 

 iron, are we illustrating more than a very complicated form 

 of the match's response to the friction ? According to Dr. 

 J. S. Haldane, we are. " In identifying stimulus and 

 response with physical or chemical cause and effect, the 

 mechanistic theory makes a gigantic leap in the dark." 



When the sun's rays passing through a knot in a roof -light 

 set fire to a heap of cotton-waste and the flames spread till 

 they reach a barrel of gunpowder, which explodes, and other 



