22 SYMBIOGENESIS 



It may be that there has been, as Prof. Bergson suggests, 

 an impetus of evolution, an immense impulse behind life to 

 climb higher and higher, to run greater and greater risks in 

 order to arrive at greater and greater efficiency, something 

 that ever seeks to transcend itself, and, it may be, something 

 that partakes of the nature of consciousness. But whilst this 

 remains problematical, one thing is certain, viz., that without 

 this perfecting of mutuality and co-operation in the organic 

 world as foreshadowed already by the most primitive of 

 organisms, the long ascent of life with which we now stand 

 face to face would not have been possible. 



Although Prof. Keeble shows that in C. roscoffensis the 

 photosynthesised sugar streams away as such to the colourless 

 cells of the animal, only the surplus being stored as starch, 

 and that this phenomenon has its parallel in the fact that 

 trees, for instance, similarly elaborate, store, and (in due 

 season) yield their manifold productions (starch, oil, fat, etc.), 

 he shrinks from drawing any bio-economic implications. To 

 him apparently the animal merely helps itself, i.e., steals 

 the products of the life-energy of some plant to supply it 

 with the dynamic leverage for its activities. Yet if, as he 

 contends, the relation between the coloured chlorophyll- 

 containing cells, and the animal tissues in the Convoluta 

 presents " the closest parallel with the relation which obtains 

 between the green and non-green cells of any chlorophyllous 

 plant," then surely it should not be a far cry to the proper 

 recognition of that complementary interaction, that symbiosis 

 between animal and plant, which on a grand scale obtains in 

 the organic world. The only difference is that we have in the 

 wider and more complex biological symbiosis a physical separa- 

 tion of the partners, whilst in the more primitive local and 

 domestic instances of symbiosis the partners remain closely 

 united. But this is exactly on a par with sexual separation, 

 and certainly should not perplex a biologist. It is surprising 

 how few biologists can rid their minds of the prejudice that 



