21 8 LAMARCK, HIS LIFE AND WORK 



ferring to the warm-blooded animals alone, " one is 

 led to conclude that they have alike been produced 

 from a similar living filament " (p. 236) ; and again he 

 expresses the conjecture that one and the same kind 

 of living filament is and has been the cause of all 

 organic life (p. 244). It does not follow that he was 

 a " spermist," since he strongly argued against the 

 incasement or " evolution " theory of Bonnet. 



2. Changes produced by differences of climate and 

 even seasons. Thus "the sheep of warm climates are 

 covered with hair instead of wool, and the hares and 

 partridges of the latitudes which are long buried in 

 snow become white during the winter months " (p. 

 234). Only a passing reference is made to this factor, 

 and the effects of domestication are but cursorily re- 

 ferred to. In this respect Darwin's views differed 

 much from Buffon's, with whom they were the pri- 

 mary causes in the modification of animals. 



The other factors or agencies are not referred to by 

 Buffon, showing that Darwin was not indebted to 

 Buffon, but thought out the matter in his own inde- 

 pendent way. . 



3. " Fifthly, from their first rudiment or primor- 

 dium to the termination of their lives, all animals 

 undergo perpetual transformations, which are in part 

 produced by their own exertions in consequence of 

 their desires and aversions, of their pleasures and their 

 pains, or of irritations or of associations ; and many 

 of these acquired forms or propensities are transmitted 

 to their posterity '/^p. 237). The three great objects 

 of desire are, he says, " lust, hunger, and security " 

 (P- 237)- 



