INTRODUCTION xvii. 



species or different species, genera, orders, etc., even in the 

 last and most fundamental way between plant and animal in 

 the web of life. By the term symbiosis I refer to that obvious 

 phenomenon of co-operation of parts and organisms as they 

 occur, while by symbiogenesis I mean the principle under- 

 lying such symbiosis and indeed all instances of mutuality in 

 the progressive transmutation of biological values generally. 

 Symbiosis, further, may be domestic when it is between the 

 organs of one organism and between the members of a family ; 

 biological when it refers to physically separate partners, even 

 when widely separated and unconscious of partnership. 



Coming back to the importance of nutrition and its 

 parallelism with sex, it may be noted that Samuel Butler went 

 so far in his biological visualisation as to say that eating is a 

 mode of love, and that "Food is very thoughtful; through 

 thought it comes, and back through thought it shall return," 

 which is another way of emphasising the amphimixis aspect of 

 nutrition. Eating, I should say, is a mode of love precisely 

 in so far as it is an instrument of symbiogenesis. 



Love is regarded as the greatest power on earth, and again 

 this may be said to be so because Love may be primarily 

 viewed as a symbiogenetic power. "L'amor che muove il sole 

 e 1'altre stelle." 



"L'union fait la force" is another statement expressive 

 of a similar idea. Biologically speaking, I should say: "La 

 symbiose fait la force." 



Even the bio-chemist's " biotic " energy, I am inclined to 

 consider as but symbiotically compounded organic energy and 

 organic experience. The fact that substances differ in their 

 intra-atomic and general constitution as well as in their 

 effectiveness, according to their origin, and that, further, 

 " every form of protoplasm existent in any organism is stereo- 

 chemically ordered in specific relationship to that organism, 

 so that the products of synthesis have an impressed structure 

 and manifest optical activity" (Nature, 9/7/14, p. 491), 

 viewed in the light of symbiogenesis, suggests that every 



