36 PHYSICAL INVESTIGATION. [PART 



. 



another opinion of Foissac, which attributes the tawny colour 

 of the Polar nations to the diminished absorption of oxygen, their 

 blood being charged with carbon, owing to the hot summers and 

 the heated and smoky winter habitations. Though some of these 

 circumstances may have their share, it cannot be ascertained to 

 what cause the colour of the Polar tribes is chiefly due. Hence, 

 the assumption of specific peculiarities is still permissible. We 

 are, therefore, obliged to rest satisfied with a mere probability 

 regarding the causal connexion of climatic influences and ali- 

 mentations, with physical peculiarities ; and frequently even 

 probability fails us. 



It is this impossibility to analyze the effects of climate and 

 nutrition which has induced Grodron 2 to assert that climate has 

 but a superficial influence on plants and animals and could have 

 contributed but little to the differences of human races ; and 

 that the causes of the latter lie rather in the differences of 

 nutrition and modes of life : for whilst some plants and animals 

 thrive unchanged in different climates, the wolf and the fox retain 

 the same characters in the torrid or the frigid zone, like the 

 wild horses in South America which possess the same charac- 

 ters as those of the Crimea and Ukraine. 



The influence of climate as a general agent cannot, however, 

 be called in question. We may quote the well known facts 

 mentioned in detail by Heusinger, 2 that in cold climates, the 

 size, growth, sexual development, and prolificacy of animals 

 diminish, whilst hair and feathers grow more abundantly ; fatty 

 deposits are found, and the colour becomes white, whilst the 

 contrary occurs under the tropics. Many of our domestic ani- 

 mals which thrive in different climates, present the most evident 

 examples of these influences. 



How much the human economy can adapt itself to climatic 

 conditions, is proved chiefly by climatic diseases and the morbid 

 predispositions peculiar to every climate ; and though the con- 

 sequences are not always a visible change of the external form, 

 the modifications in the vital process are undeniable. It fre- 



1 " De I'Esp&ce et des Races," p. 16 and 70, Nancy, 1848. 

 a "Grundziige der Vegl. Physiol.," p. 211, 1831. 



