SYMBIONTICISM AND ORGANIC EVOLUTION 137 



Symplasm in the life cycle of bacteria represents a tem- 

 porary fusion stage somewhat akin to conjugation, but 

 more intimate in character. Even in this process, we can 

 account for a mechanism in bacterial variation that coin- 

 cides with that embodied in SjTnbionticism. The possi- 

 bility of foreign bacteria with harmonious prototactic prop- 

 erties being engulfed or ''drawn into" a bacterial symplasm 

 appears feasible. Such bacterial contact would allow for 

 a modification of the individual bacteria after they had 

 separated from the sjanplasm. 



The conception that "bacterial fusions" have been the 

 fundamental factor in bacterial evolution or variation, is 

 necessarily hypothetical, but it is in harmony with the 

 principle of Symbionticism, and it appears to the author 

 that it offers a rational explanation with at least some 

 ''circumstantial evidence" to support it. To what extent 

 environmental influences may enter into the process of 

 bacterial evolution is difficult to analyze even in a specu- 

 lative way. Certainly, if enviroimiental influences can 

 modify free-living bacteria and produce permanent modifi- 

 cations, then we are justified in assuming that they may also 

 operate in the origin of higher organisms. However, it re- 

 mains to be shown whether the modifications produced in 

 bacteria by environmental factors are transitory or of a 

 permanent nature. It is difficult to understand how en- 

 vironmental influences alone could, for example, bring 

 about changes in a group of cells or a microorganism that 

 would result in the production of an entirely new chemical 

 product. On the basis of our experiences with chemical 

 reactions, it is easy to understand how bacteria of different 

 potentialities might combine to produce a new organism 

 wdth properties differing from those of either component. 

 Just as in chemical reactions a certain combination of 

 extrinsic factors are necessary if the reaction is to take 

 place, so it is safe to assume, that environmental factors 



