2\tt SYMB10GENESIS 



with the poison, and its general symbiotic po\vers so far as they 

 are not yet impaired are summoned to a great eliminative 

 effort. 



The symbiotic forces, however, w r hen they are habitually 

 wasted on such " warfare," are turned away from their proper 

 channels, and just as we have seen a weakening of the higher 

 symbiotic powers of an organism to be the cause of a frequent 

 over-emphasis of vegetative growth at the expense of sexual 

 development, so every morbid "infection" (apart from its 

 draft on vitality) may check " higher " development and lead 

 to retrogressive adaptation. 



Let us take as another biological illustration of the prin- 

 ciple with which we are here concerned the case of the crab 

 infected with a parasite, viz., Sacculina, as pointed out by 

 Geoffrey Smith (in a paper read before the British Association, 

 1913). In crabs of both sexes so infected we do not find any 

 of those cyclical changes of reproduction and of growth taking 

 place such as occur normally in animals. Such crabs neither 

 grow, moult, nor reproduce. What symbiotic powers there are 

 in these hosts are too fully engaged in coping with the intruder 

 whom they must tolerate because they lack the power to 

 expel. Sex and evolution consequently are sacrificed. The 

 crab is thus forced into a retrogressive adaptation (a slow form 

 of pathogenesis). It has to provide a larger percentage of fat 

 than in the normal (cyclic) life, and its amount of lutein (con- 

 nected with vital bio-chemical stimulation productive of cyclic 

 changes, i.e., with the general metabolism and thus with bio- 

 economic function) in the blood is correspondingly diminished. 



It has to satisfy demands which are exorbitant and there- 

 fore no longer symbiogenetic. Both organisms suffer from a 

 distorted relation between demand and supply. " Ainsi 

 Phistoire pese lourdement sur la nature. Quand un organisme 

 vit en parasite d'un autre, c'est le plus faible qui triomphe, 

 sans qu'il yait amelioration ni d'une espece ni de 1'autre. 

 L'exces de 1'inegalite economique empeche les inegalites 

 naturelles de se mesurer utilement " (Bougie). 



