CHAPTER IX 

 GENERAL CONCLUSIONS 



Now that we have come to the end is it possible to arrive at any generaHsations, 

 or to detect any pattern in the complexity of data ? It is evident that in addition to 

 the wide variety of physiological processes that are primarily oxidation-reduction 

 reactions there are a host of others which are governed or modified directly by 

 oxidation-reduction conditions. The few reactions that do not fall into these two 

 categories are linked with other reactions in which oxidation-reduction potentials 

 play a supreme role. 



Perhaps one of the outstanding conclusions one can draw from the trend of 

 modern work is the accumulating evidence of the inter-dependence of apparently 

 independent processes. Reactions occur in chains and interference with one link 

 ruptures the whole chain ; a reaction occuring early in a chain is closely linked with 

 another near the end. The catalytic effects of enzymes are so nicely balanced and 

 the partnership of coenzymes so close-knit that incredible feats of synthesis or break- 

 down occur almost isothermally at amazing speed. 



Whereas a few years ago metaboUc reactions were being studied in detail 

 separately, it now begins to be possible to visualise broader plans of free energy 

 changes, of cell synthesis, of phosphate cycles, of the oxidation-reduction balance. 

 The harmonies are so finely adjusted that it is disconcerting to find an organism 

 producing a substance that is not purely utilitarian and designed exclusively for the 

 most efficient functioning of a metabolic process. The beauty of the pigments of 

 wild flowers seems excessive for mere survival and the synthetic galaxies of the moulds 

 appear to be exclusively for the humbhng of organic chemists. 



It is not surprising to find so many mould pigments and products to be related 

 to the quinones, naphthaquinones and anthraquinones, all subject to study by 

 oxidation-reduction potential methods and possibly of metabolic significance, but it 

 is more surprising to find closely related compounds of significance in widely different 

 organisms far distant in the genealogical tree. Frequently the metabolic process of 

 the bacterium, the yeast cell and the mammahan muscle follows a similar course, 

 despite the difference of medium and of organisation. 



Nucleic acids play their predominating role of directing synthesis and differen- 

 tiation in virus multiphcation, in bacterial type differentiation and in animal 

 chromosomes. The clue to the puzzle of self-multiplication is bound up in the nucleic 

 acids and their role of providing patterns for the shaping of protein syntheses. 



The same vitamins and growth substances are needed for man and microbe, and a 

 vitamin assay is now more the task of a bacteriologist than a physiologist. But all 

 these harmonies must not blind us to the differences. Possibly, just as the last two 

 decades have shown us the similarities of widely different organisms, the next two 

 may make plainer the differences — the control of cancerous growth, the defeat of the 

 virus and the checking of infectious diseases depend upon our finding agents lethal to 

 one type of cell, but harmless to another. Possibly hormonal control too may result 

 from our finding antagonists to hormone production, as indeed is already suggested 



