OF ARTS AND SCIENCES. 177 



remarked, but also the one which, on applying it to the case in 

 hand, he thought best adapted to explain the actual distribu- 

 tion of plants. Although not inclined to defer too much to 

 a priori reasoning, he thought it was suggested by philosoph- 

 ical considerations, as well as by the induction of observa- 

 tions ; being a natural inference from Maupertuis's principle 

 of least action, viz. "that it is inconsistent with our idea of 

 Divine Wisdom to suppose that God would use more power 

 than was necessary to accomplish a given end." According 

 to Professor Peirce, this principle is strictly verified in all the 

 mechanical arrangements of the universe ; so that we cannot 

 but think it applicable to the organic world also ; — in which 

 there would appear to be a vast waste of power, if, in the case 

 of beings endowed with such immense multiplying power as 

 plants, as many individuals were created ab initio as there 

 were ever subsequently to be. 



The discussion was continued by Professor Agassiz, who 

 remarked that Professor Gray had fairly represented his view 

 of the origin of animals. Botanists, he said, have considered 

 the distribution of plants mainly in connection with the influ- 

 ence of physical agents, whereas zoologists had regarded the 

 distribution of animals from a palsBontological point of view, 

 and from this latter point of view he had himself been led to 

 the opinion that animals were primarily distributed about as 

 they are at the present time. 



Professor Agassiz argued that climate has very little to do 

 with the distribution or specific characters of animals, from 

 the facts observable at the present time. Near the poles, he 

 remarked, the conditions of existence are quite uniform, and 

 in the tropics they are the same so far as climate is concerned. 

 In the arctic regions we find many animals absolutely iden- 

 tical in both hemispheres, and many very closely related to 

 each other ; in the regions of the tropics, on the other hand, 

 there is no similarity in the animal life of the two hemispheres, 

 although the climate is the same. It is evident, therefore, that 

 the peculiar characters of the Faunas of these regions cannot 



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