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 E 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 

 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 F* be 

 FlG 6 ~ ' but a Hydrogen or Hydroxyl 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 s 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 



