m.] ECOLOGISTS' VIEWS 27 



" I answer briefly to the question which arises, 

 namely, whether these adaptations to the 

 medium should be regarded as a result of 

 natural selection, or whether they owe their 

 origin to the action, in modifying forms, 

 exercised directly by the conditions of the 

 medium. / adopt this latter view . . . the 

 characters of adaptation thus directly acquired 

 has become fixed." 



Similarly, M. Costantin, speaking of Arctic 

 plants, says : 



" We are led to think, so to say, invincibly, 

 that one can only explain the general characters 

 of Arctic plants by adaptation e.g., if all Arctic 

 plants are perennial, it is because they live near 

 the Pole. It is the conditions of life which have 

 caused this hereditary character." : 



Though both Dr Wallace and Dr Weismann 

 are "Darwinians" yet they cannot help taking 

 the opposite view when striking cases come 

 before them ; Dr Wallace observed that local 

 varieties of butterflies and other groups of insects 



"seem to indicate that climate and other 

 physical causes have, in some cases, a very power- 

 ful effect in modifying specific form and colour, 

 and thus directly aid in producing the endless 

 variety of nature." 3 



Similarly Dr Weismann came, eighteen years 

 afterwards, to precisely the same conclusion, for 

 he says: 



1 " Lagoa Santa," p. 465. 



2 " Les Vegetaux etles Milieux Cosmiques " ; also " La Nature 

 Tropicole." 



* "On Natural Selection," p. 179 (1877). 



