824 president's address. 



When the infallibility of the dogma of fixity of species had 

 been seriously questioned by men like Linnaeus and Bulfon, the 

 first and very momentous step had been taken in the direction 

 of the modern standpoint. From this time forth transformist 

 ideas never lacked adherents, though the issue of the conflict 

 with the conservative doctrine of fixity was, owing largely to the 

 later overwhelming influence of Cuvier, for long to remain doubt, 

 ful. Meanwhile the problem for the transformists became even 

 more complicated. For, supposing it to be granted that structural 

 modification of organic forms has actually occurred, the question 

 then arises : " How, and by what agencies, are we to suppose 

 that this transformation has been efiected T In other words, 

 what are the factors in the hypothetical process of evolution 1 



In attempting to answer this question the cardinal biological 

 fact of adaptation between organism and its environment stood 

 forth as above demanding recognition and explanation. 



How could this harmony or unity be imagined to have been 

 attained and preserved alongside of, and perhaps in spite of, 

 disturbing modifying influences 1 Two possible answers obviously 

 presented themselves from the naturalistic point of view. Either 

 the direct operation of environment has determined structural 

 change and variation in a passive and plastic organism in the 

 direction of harmony with itself ; or, on the other hand, the 

 initiative must in some sense have come from within the organism. 

 The latter must then be conceived as an active agent which, 

 under the pressure of an internal " organic necessity," adapts 

 itself, though in reaction to environment, by actual if slight 

 structural alterations. Further, such acquii'ed changes, the 

 results of constant habitual and useful adaptation to a changed 

 or changing environment, are permanently embodied and handed 

 on to the offspi-ing by inheritance. 



The pre-Darwinian evolutionists may be ranked as adherents 

 of the one or other of these explanatory hypotheses. The elder 

 St. Hilaire may represent those who, with BufFon himself, chose 

 the first alternative, whilst the name of Lamarck is now insepar- 

 ably linked with the second. 



