226 SYMBIOSIS 



superiority of a relation of tolerable Symbiosis to one that is 

 merely of the nature of an " unholy alliance," albeit the difference 

 is still between cross-feeders. 



If, as the author says, " in carnivorous animals and mixed 

 feeders another factor comes in," this is only too true. It is the 

 adaptation of the mouth to " killing," which constitutes the new 

 and complicating factor, although the author seems very chary of 

 allowing the full significance of the matter. The fact of " killing " 

 altogether alters the case, and apart from the author's data, there 

 are other and some very far-reaching injurious reactions of 

 sanguinary habits to be borne in mind. There are, for example, 

 the long fangs, entailing, because of their exorbitant demand 

 of blood-supply, a much reduced brain ; there are the ferocity 

 and thriftlessness of the beast, unfitting it for the industrious 

 and the social life ; the diminished Phagocytosis and consequent 

 impoverishment of the blood all testifying that bestiality is 

 on all counts the surest bar to progress. I have already instanced 

 the fact that food borne infection is very common amongst Carni- 

 vora and Omnivora. Our food-plants are not attacked by any 

 micro-organisms pathogenic to man or to animals ; but our 

 domestic slaves, which we kill for food, suffer from bacterial 

 infection, and this is communicable to man. All of which is 

 calculated to throw light on the way in which " killing " is 

 pregnant with injurious reactions upon the predatory organism. 

 Again, there is the fact, established by Richet and other Physio- 

 logists, that fruit and vegetables with the exception of a few 

 over-cultivated ones never give rise to " Alimentary Ana- 

 phylaxis " (the dietary equivalent of serum-disease), whilst flesh 

 foods often produce the same distressing symptoms upon body 

 and mind as are known frequently to result from a direct intro- 

 duction of protein poisons into the blood, which again shows the 

 case of the in-feeder in general to be very inferior to that of the 

 cross-feeder. Facts such as these, I consider as of almost 

 inconceivable importance in evolutionary anthropology. They 

 far outweigh anything of evolutionary import that can be 

 advanced on merely anatomical grounds. As regards the recession 

 of the jaws and the more or less connected reduction of the tooth 

 series, we are further told : 



With the business of hand-feeding, Man has gone a great deal farther 

 than any other member of the Primates, and that comparatively modern 

 development civilised Man has gone still farther. The highest Primates 



