8 SYMBIOGENESIS 



This is more particularly apparent so far as photosynthesis 

 is concerned, the special manufacturing process of the plant 

 the most wonderful example in the world of life of systematic 

 and vital work unceasingly and ungrudgingly performed. 

 Experimental Morphology has shown that a reduction of the 

 general production of organic substances (especially of carbo- 

 hydrates) by a plant can be brought about in many cases by a 

 diminution of the intensity of light, which interferes with its 

 photosynthetic process of manufacture. In view of the fact 

 that the general productiveness of a plant determines its status 

 in the biological scale, we see how emphatically the evolu- 

 tionary position and fate of a plant must depend on work. In 

 the case of a plant an artificial diminution of its usual output 

 of biologically valuable substances is generally attended by an 

 undue predominance of vegetative growth at the expense of 

 sexual development: all of which makes for retrogression as 

 we shall see more fully later on. The assimilation of carbon 

 by a plant is, of course, part of its photosynthetic process of 

 manufacture, and Prof. G. Klebs* states that it is essential to 

 the sexual reproduction of algse, for instance, that a 

 " vigorous production " of the materials formed during carbon- 

 assimilation should take place. All his evidence from the point 

 of view of Economics and still more of Bio-Economics must be 

 interpreted to mean that work (productiveness) is the one great 

 essential to progressive life. That, inversely, cessation of 

 work for any length of time, universally (in the case of all 

 organisms) leads to degeneration is, of course, a well-known 

 phenomenon. 



According to this evidence, then, I am scarcely making 

 too much of this point of "work " in representing it as of at 

 least equal importance in organic evolution as it is, according 

 to the " gospel of work," in human civilisation. 



But, it may be asked, does not this theory of Bio-Economics 

 perhaps make too exorbitant a demand on the willingness 



* See his contribution to Darwin and Modem Science. 



