266 SYMBIOSIS 



Commensalism " is but a trivial, if not retrogressive, form of 

 organic association from which we cannot expect great results 

 of evolution. 



Open-mindedly enough, Prof. Bernard concedes, as an 

 alternative to his general view on the subject, that many of the 

 special structures of the orchids, so far from being due to 

 " Commensalism," may be merely due to epiphytism and 

 saprophytism : 



Je ne nie pas que des conditions diverses indiquees par ces modes 

 de vie aient pu avoir une action sur 1'evolution des vgetaux qui les accep- 

 tent ; quelques traits de leur organisation peuvent sans doute s'expliquer 



ainsi. 



And he has the intuition to see that organisms may somehow 

 become liable to what I consider retrogression, because of their 

 having to propitiate associated parasites or quasi-parasites. To 

 quote his own words : 



On peut aller plus loin et penser que 1'aptitude a 1'epiphytisme ou au 

 saprophytisme a pu se developper chez les Orchidees, originairement ter- 

 restres et non saprophytes, justement par suite de Faction sur ces plantes 

 de leurs champignons commensaux, la symhiose ay ant entraine a la fois 

 1'apparition de caracteres morphologiques nouveaux et de dispositions 

 physiologiques particulieres. 



If Prof. Bernard had but gleaned his lessons from Symbiosis 

 proper instead of confining himself to " Symbio-Commensalism ! " 

 Whilst it is quite true, and even specially significant, that life 

 and evolution are pre-eminently determined by the nature of the 

 organism's associations, yet we may be certain that the extreme 

 determination of the proud orchids by the lowly fungi a 

 determination away from Norm- and increasingly towards 

 Luxury-Symbiosis must have been preceded by some morbid 

 factor, by some predisposition to " infection " on the part of 

 the orchids. And this predisposition, in my view, was due to 

 an incipient form of in-feeding. An in-feeding diathesis, however 

 mild at first, determined the retrogressive evolution of the orchids. 

 The fungi merely played an adventitious part in it; their presence, 

 inter alia, augmenting the craving for in-feeding, i.e., for 

 saprophytism. 



To the fungi, the symbiotic association with the orchids for 

 the most part means strenuousness and abstinence from 

 pronounced saprophytism. 



Whilst telling us that they are apt to lose their " proprietes 



