234 SYMBIOSIS 



are prone to have inhibiting and unbalancing effects, apt to 

 introduce components of " over," rather than of normal specialisa- 

 tion, of " contre " rather than of progressive evolution. The 

 craving for such food is in itself proof positive that short cuts 

 and felonious excursions rather than legitimate roads and 

 physiological righteousness are desiderated by the respective 

 species. We have, however, every reason for thinking, on the 

 other hand, as has been shown in the foregoing pages, that the 

 highest kind of development is associated with that kind of food, 

 the getting of which is legitimised by uncounted ages of mutual 

 evolution of animals and plants, and entails some kind of counter- 

 service and corresponding equipment for service on the part of 

 the animal. Complete diet, complete work, and complete 

 evolution go together " complete " implying all, but no more, 

 than is necessary in the highest interest of " organic civilisation. " 

 I believe I have to some extent shown that cross-feeding was 

 primitive, and that, inasmuch as it is associated with useful 

 partnership, it is indeed of the very essence of progressive evolu- 

 tion. I have emphasised that if, according to Prof. Wood Jones, 

 in the details of its skeletal elements, the fore-limb of the highest 

 of the mammals finds its likeness among living Vertebrates in 

 such a modest, sociable and inoffensive creature as the tortoise 

 remarkable also for its short-snoutedness this animal belongs 

 to an essentially cross-feeding stock. There is much inherent 

 probability, therefore, that the chief distinction of the human 

 stock consisted in long continued faithfulness to the primitive 

 virtue of symbiotic cross-feeding. This would be in 

 complete agreement with man's primitive anatomical simplicity 

 as pictured by Prof. Wood Jones in his The Problem of Man's 

 Ancestry, where he states (p. 31) that 



No monkey or anthropoid ape approaches near to man in the primitive 

 simplicity of the nasal bones. The structure of the back wall of the orbit, 

 the " metopic " suture, the form of the jugal bone, the condition of the 

 internal pterygoid plate, the teeth, etc., all tell the same story that the 

 human skull is built upon remarkably primitive mammalian lines, which 

 have been departed from in some degree by all monkeys and apes. The 

 human skeleton, especially in its variations, shows exactly the same con- 

 dition. As for muscles, man is wonderfully distinguished by the retention 

 of primitive features lost in the rest of the Primates. 



No doubt, the monkeys had not remained as wisely conservative 

 in the matter of cross-feeding as had the primitive human stock, 

 and in Arboreal Man, Prof. Wood Jones tells us that the 



