6 SYMBIOGENESIS 



and "historic" for "natural," i.e., mechanical, or 

 involuntary or "non-artificial" phenomena. 



En mtjme temps rejetant les origines du phenomene de la division 

 du travail dans un passe infiniment lointain, il [le progres biologique] 

 nous deshabituait de le regarder oomme une oauvre en quelque sorte 

 artificielle, issue d'un contrat debattu entre echangistes. Rattacher, 

 comme a son principe unique et uiiiversel, la division du travail a 

 1'echange commerciel, c'etait prendre un accident pour 1'essence, une 

 "categoric historique " pour la forme naturelle et necessaire. 



Prof. Keeble does not bind himself to either a mechanical 

 or a teleological view. He will not rest content with a teleo- 

 logical explanation. 



To say that this animal does such and such a thing because it is 

 convenient or useful for it to do that thing is to renounce profound 

 investigation. Before this can be regarded as the proper philosophical 

 attitude towards life, the resources of chemistry and physics must be 

 exhausted, and the behaviour under consideration must at least be 

 proved not to be due to a chemical or physical change induced by some 

 factor or factors of the environment. 



In other words, the least the physiologist can do is to attempt to 

 discover how the adaptive trick is performed by the animal which 

 exhibits it. 



The truly philosophical view can only gain if such full 

 physiological and chemical investigation of the phenomena of 

 adaptation be supplied. I here, also, find myself in com- 

 plete agreement with Prof. Bergson, who holds that philosophy 

 must take account of all the sciences have to offer, that theory 

 of knowledge and theory of life are inseparable, and should 

 push each other on unceasingly. 



As regards the particular form of adaptation showing 

 itself in the periodicity of reproductive processes in Convoluta, 

 we are told that it is " for one reason or another " ultimately 

 connected with nutrition. This is of special importance for 

 my contention. With nutrition the ground is shifted from 

 mere Chemistry and mere Physiology to a subject that, though 

 it must include both, yet is greater than either, viz., Bio- 

 Economics. As soon as we study nutrition in its wider aspects 

 production, distribution, and the concomitant biological inter- 



