270 SYMBIOGENESIS 



though retrogressively and for a time, to change almost 

 indifferently and indefinitely. If Prof. Henslow, who speaks of 

 depauperised plants (some species of different genera have been 

 actually named depauperata, the degraded characters having 

 become fixed and hereditary), were more thoroughly consistent, 

 he would speak of self-pauperisation as the antithesis of pro- 

 gressive self-adaptation ("self-made" plants), instead of 

 which he pleads that the causes of degeneracy reside in the 

 external agencies (although otherwise fully admitting that 

 parasitism is also a factor of degeneracy). Apparently he is 

 influenced by the fact that degenerations in plants are so 

 numerous as to appear almost normal. Such errors are 

 clearly due to the non-appreciation of the bio-economic 

 factors. Production, in spite of all degeneration, remains pre- 

 dominant, and, what is more, measured by degrees of 

 productiveness, it is possible to make the vital distinction 

 between progressive "degeneration," i.e., atrophy of the 

 biologically useless, and retrogressive degeneration, i.e., 

 atrophy of the biologically useful. How sadly such 

 standardisation is wanted is thus again evidenced by Prof. 

 Henslow's writings. 



K. VARIATION. 



Under this heading, Spencer notes that the transmission 

 of variations is itself variable, and that it varies both in the 

 direction of decrease and in the direction of increase. 



An individual trait of one parent may be so counteracted by the 

 influence of the other parent that it may not appear in the offspring; 

 or not being so counteracted the offspring may possess it, perhaps in an 

 equal degree, or perhaps in a lees degree; or the offspring may exhibit 

 the trait in even a still higher degree. 



We thus get an illustration of the possibilities of 

 amphimixis and of the play of opposites determined in the 

 long run as to its results, by values, as we have seen in the 

 chapter on Genetics. In illustration of this proposition, 

 Spencer cites the case of the transmission of six-fingeredness in 

 certain families, and although he fails to draw the line between 



