36 CRITICISM OF MECHANISTIC THEORY 



response implies equal failure in tracing the 

 stream of matter or of energy through a living 

 organism. We cannot tell what exactly be 

 comes of the atoms and molecules which pass 

 into the body how far, or in what sense, they 

 are built up into the living tissue, or in what 

 way their potential energy is immediately 

 utilised. We must not mistake measurements 

 of the balance of matter or energy entering 

 and leaving the body, for information as to the 

 manner in which this stream passes through 

 the living tissues. 



In the previous lecture we saw that in the 

 historical development of physiology there 

 has been a continuous accumulation of facts, 

 obtained by the application of physical and 

 chemical methods to physiological phenomena. 

 The limits which the vitalists have attempted 

 to set to this accumulation of knowledge have 

 been broken down again and again, and there 

 is no reason to suppose that there are any 

 limits. The leaders of the mechanistic phy 

 siology have been completely justified to this 

 extent, and we may rest assured that to this 

 extent physiology will never go back on the 

 step which they took. Our knowledge as to 



