THE BASIS OF VARIATION

The sense of likeness and the sense of unlikeness plays a decisive role in the diurnal schedule of the individual.  His sense of resemblance to his father and mother, his kin and clan, mark him and them off against the cosmos as an alliance of defense and offense.  Yet no matter how closely he is like them and they like him, he differs and varies, they differ and vary, with a sort of mutual forgiveness, because the amount of resemblance overtops the degree of variation.  In a paper on the “Rediscovery of the Unique,” H.G.  Wells emphasized the unique quality of the individual, and how, in spite of the cleverest devices of classification, living things ultimately escaped the classifying net by virtue of their tendency forever to vary.

The individual is unique.  Yet when all is said and done, the fact remains that between individuals there is resemblance, and among them variation.  What is the reason for their resemblances and what is the cause of their variation?

The conception of a particular chemical make-up of the individual, statable and relatively controllable in terms of the internal secretions, supplies a more rational and satisfactory method of approach to the problem than any so far suggested as far as vertebrates are concerned at any rate.  In effect, the differences between individuals may fundamentally thus be grouped among the differences which distinguish other chemical substances.  The difference between water, technically known as hydrogen monoxide, and the antiseptic fluid labeled hydrogen dioxide lies wholly in the possession by the latter of an extra atom of oxygen in its molecules.  All the peculiarities and qualities by which hydrogen peroxide is separated from water are referred to that additional quantum of oxygen.  So the diversity of constitution and appearance of two brothers, alike in that they have inherited the same internal secretion trends, may be traced to the superiority of the pituitary of the one over the other.

Variation and resemblance are large issues, crucial material of the science of biology upon which much has been thought and written.  That the proportion of the endocrines determines variation and resemblance, heredity and evolution is a hypothesis advanced, supported by a large amount of facts, and capable of the most interesting experimental verification and observation.  If a child resembles particularly either of its parents, grandparents or relatives, there is good reason for believing that it is because their endocrine formulas are very much alike.  When people apparently not blood-related at all resemble one other, the same law must hold.  Resemblances may be partial or complete, and the degree will depend upon the amount and ratio of the internal secretions involved.