86 ADAPTATION AND DISEASE 



up, or katabolism, breaking down — the more it is borne in upon 

 us that the greater number — some would say all — are the out- 

 come of enzyme action. 



(iv.) On Enzyme Action. — This is not the place to discuss 

 the nature of enzyme action in detail. For the most authorita- 

 tive treatment of the subject Professor Bayliss's works should 

 be consulted. Suffice it to say that the simplest and now gener- 

 ally accepted view is that there exist in the cell, and are dis- 

 charged from it, intermediary bodies — katalysts — which promote 

 and hasten chemical dissociations and associations without them- 

 selves being involved in the final stage, and that the simplest 

 diagrammatic representation of their action is as indicated in 

 the diagram in which F represents the go-between, the body 



endowed with enzyme action, S the 

 substratum or body which undergoes 

 dissociation, and R the receptor 

 or body which is aggrandized, with 

 which the dissociated moiety or 

 f j part of the substratum enters into 



union. There are, I hold, always 

 these two phases of dissociation 

 and association in each instance of 

 ferment activity, even if R be 

 F 6 but a Hydrogen or Hydroxy 1 ion. 



The process is comparable with the 

 katalytic process of manufacture of concentrated sulphuric acid 

 from sulphurous anhydride, through the agency of nitrous acid. 

 The nitrous acid HNO ? takes up a molecule of from the air, 

 becoming nitric acid, and acting as carrier gives this over to the 

 sulphurous anhydride H 2 S0 3 , converting this into sulphuric acid 

 H 2 S0 4 , with this becoming free itself to take up another molecule 

 of oxygen and repeat the process with another molecule of sul- 

 phuric anhydride. And the process continues until a certain 

 equilibrium is reached between the amount of anhydride and of 

 sulphuric acid present, unless the H 2 S0 4 be removed so soon 

 as formed, in which case eventually a trace of nitrous acid can 

 convert a maximum, or theoretically infinite, amount of anhydride. 

 And this action is under certain conditions reversible. 



Now, as I have already stated, the evidence is conclusive 

 that none of the ordinary food-stuffs — the proteins, carbohydrates 



