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 tt to represent that interminable 

 fraction 3*14159265 . . . etc. 



V 

 •A 



I vi. 



V, 



<»•-••• 



».• 



Y\ 



ll]^>-^llllip^- 



« / » 



• t • ' 



H N 



Fig. 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 life 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 wav in which these unsatisfied arms become satisfied — 



