SYMBIOSIS 3 



factor in the evolutionary process, and that, whereas adequate feeding 

 is indispensable to orthogenesis, a super-adequacy of force, derived from 

 a nutritional basis, is needed to achieve rise of type. He finds every- 

 where throughout organic nature evidence of a symbiotic reciprocity, 

 so that healthy organisms and thriving species may be compared to 

 tiuding individuals and communities, whose claim to survival rests on 

 the production of commodities or the rendering of services indispensable 

 to others. He believes that there is a law relating to nutrition analogous 

 to that stated by Darwin with regard to fertilization, which, in 

 corresponding terms, runs thus: " Nature abhors perpetual in-feeding." 

 By the term " in- feeding " he denominates the indolent appropriation 

 of food manufactured by close relatives, and the correlated shirking of 

 the economic duty of production, or of mutual service in some kind. 

 By the term "cross-feeding," on the other hand, he designates what he 

 conceives to be the norm of healthy nutrition, since he finds in the 

 properly matured products of plant life food material ideally adapted 

 to the requirements of the animal world. His main objection to 

 Darwinism is that it makes the mere fact of survival the criterion of 

 biological success and value, whereby the liver-fluke becomes the peer 

 of the philosopher. But, in the author's view, parasitism is the last 

 stage of a pathological process, of which insectivorism is an early and 

 carnivorism the intermediate manifestation. 



In the present chapter it will be my endeavour to deal 

 more fully with the far-reaching importance of symbiosis, and 

 to show that the new knowledge to be gleaned from its study 

 especially if it is duly complemented by my own and other new 

 conceptions now gaining ground in the various provinces of 

 science is precisely calculated to fill that hiatus in Darwin's 

 theory, which on his own admission (as stated above) was 

 bound to remain so long as such knowledge was lacking. 



In a useful and fascinating' little work on Plant-Animals : 

 A Study in Symbiosis, Prof. F. Keeble shows how the study 

 of the lower forms of life is of importance towards a fuller 

 understanding of the more complex higher forms. The 

 eminent botanist states that the higher the organism, the more 

 it has covered up the tracks along which the species to which 

 it belongs has travelled, and that for this reason alone the 

 study of the lower organisms is not only to be justified but also 

 urged on zoologists, as one bound to lead to results of the 

 greatest value. But though this be so, our business in 



