MALADIE ET SYMBIOSE 269 



But the facts are capable of a different interpretation. The 

 fungi, in my opinion, only gain paramount influence inasmuch 

 as the orchids, qua in-feeders, have become indolent and degene- 

 rate ; whilst the increasing intimacy does not constitute genuine 

 progress in Symbiosis at all. 



That in Norm-Symbiosis the partners have to make mutual 

 concessions and to some extent mutually to determine each 

 other, is, of course, a different matter one that emerges from 

 the study of such Symbiosis without the need of referring to 

 " Selection " at all. 



A similar criticism applies to the following of Prof. Bernard's 

 statements, though feasible enough by itself : 



La possibilite de progres correlatifs de 1'activite des champignons, 

 de la symbiose et de 1'evolution des Orchidees, est done theoriquement 

 concevable. Mais si elle correspond a une realite, il doit en rester des 

 preuves ; on doit trouver chez les Orchidees les plus evoluees des cham- 

 pignons plus actifs que chez les Orchidees les plus primitives ; il doit y 

 avoir un rapport constatable entre le degre d'activite des champignons 

 et le degre d'evolution de leurs hotes. 



Granted such correlative progress, there still remains the 

 question : Are we on the whole dealing with progressive or with 

 retrogressive evolution, and which are, in either case, the 

 respective criteria ? Is the correlation connected with healthy 

 or with morbid affinities ? And what is it that determines 

 sanctions, or limits, in such correlated evolution ? 



In the course of his investigations, Prof. Bernard interchanged 

 the " infecting " fungi, such as Rhizoctonia repens and Rhizoclonia 

 mucoroides, and this is what he found : " L'ensemble des experi- 

 ences montre clairement en definitive que le degre d'activite des 

 champignons est plus important pour les resultats que la nature 

 meme de ces champignons." 



Again, this is what one would expect on the view that the 

 study of behaviour is more important than that of classification. 

 It is necessary, however, to add that the degree of " infective " 

 fungal activity is not altogether one-sidedly determined ; it is 

 to a large measure determined by the biological activities of the 

 orchids, in particular their feeding habits. The activities of 

 associated orchids and fungi in fact are mutually determined. 

 The danger-point arises when they are too narrowly determined, 

 or when one or the other partner becomes unduly preponderant, 



