BIONOMICS 277 



making for proper symbiotic relations by an adequate 

 accumulation of sympathetic biological correspondences. 



Spencer's own "interpretation" is in part contained in 

 the following famous passage : 



Slowly but surely, evolution brings about an increasing amount of 

 happiness, all evils being but incidental. By its essential nature, the 

 process must everywhere produce greater fitness to the conditions of 

 existence, be they what they may. Applying alike to the lowest and 

 highest forms of organisation, there is in all cases a progressive adapta- 

 tion, and a survival of the most adapted. If, in the uniform working out 

 of the process, there are evolved organisms of low types, which prey 

 on those of higher types, the evils inflicted form but a deduction from 

 the average benefits. The universal and necessary tendency towards 

 supremacy and multiplication of the best applying to the organic 

 creation as a whole as well as to each species, is ever diminishing the 

 damage done tends ever to maintain those most superior organisms which, 

 in one way or other, escape the invasions of the inferior, and so tends 

 to produce a type less liable to the invasions of the inferior. Thus the 

 evils accompanying evolution are ever being self-eliminated. Though 

 there may arise the question, Why could they not have been avoided ? 

 there does not arise the question, Why were they deliberately inflicted ? 

 Whatever may be thought of them, it is clear that they do not imply 

 gratuitous malevolence. 



What is the essential nature of the evolutionary process if 

 it is not symbiogenesis ? This alone, and not a mere lethal 

 process, such as that contemplated by the specially limited 

 kind of Natural Selection which ignores all criteria but 

 immediate survival, could produce a desirable and permanently 

 successful kind of fitness, viz., symbiotic fitness, measurable by 

 definite standards of physiological and economic value and not 

 merely referable to any haphazard and temporary environ- 

 mental conditions ("be they what they may"!). 



To say that there is in all cases a progressive adaptation 

 amounts, as we have seen, to an indiscriminate mixing up of 

 varying orders of facts. The increasing momentum in the 

 direction of pathogenesis manifested by parasites, for instance, 

 is not a truly progressive adaptation, but is quite the opposite 

 of the gradual gain of symbiogenetic momentum on the part of 

 strenuous organisms, resulting in a permanent uplift in the 



