228 ON VARIABILITY AND ADAPTATION 



I think we can, and that by the use of current chemical con- 

 ventions and symbols. The actual process must, I admit, be 

 vastly more complicated than the diagram we employ can re- 

 present. But that doesn't matter. If, by the use of a simple 

 diagram, we can depict and can grasp the nature of the process, 

 then we have gained a great step in advance ; only, while using 

 such a simple diagram, we must remember that it is but a symbol, 

 it is like using the symbol w to represent that interminable 

 fraction 3-14159265 . . . etc. 





Fiq. 20. — Diagram of growth of biophoric molecules. 



Thus far I have pointed out that all vital processes are 

 manifestations of energy, and that such manifestations of energy 

 surely indicate chemical change. Thus the substance or bioplasm 

 endowed with lif e may be regarded as a single chemical substance, 

 varying, it is true, in its properties in the different species and 

 forms of living beings. If a chemical substance, then it is formed 

 of molecules. I have already given you the conception of the 

 structure of the biophore or molecule of living matter. Let us 

 reduce this to its simplest form — as a ring of carbon-containing 

 nuclei built up after the type of a benzole ring, with which the 

 chemists are familiar in the large group of benzene compounds. 

 Each nucleus of such a ring may, for our present purposes, be 

 represented by one of the more complex amino compounds 

 already referred to. Such nuclei are polyvalent — they have, 

 that is to say, multiple affinities which can be satisfied by the 

 attachment of other atoms as radicles. It will be seen that to 

 make a ring two at least of the affinities of each amino-acid 

 nucleus must be satisfied by junction with other nuclei, leaving, 

 however, other unsatisfied attachments. And it is in accordance 

 with the way in which these unsatisfied arms become satisfied — 



