214 THE PHILOSOPHY OF BIRDS' NESTS. 



great height, with an open bamboo floor; and the 

 whole structure is exceedingly slight and thin. Now, 

 what can be the reason of this remarkable difference 

 between countries, many parts of which are strikingly 

 similar in physical conditions, natural productions, and 

 the state of civilization of their inhabitants ? We ap- 

 pear to have some clue to it in the supposed origin 

 and migrations of their respective populations. The 

 indigenes of tropical America are believed to have im- 

 migrated from the north from a country where the 

 winters are severe, and raised houses with open floors 

 would be hardly habitable. They moved southwards 

 by land along the mountain ranges and uplands, and 

 in an altered climate continued the mode of construc- 

 tion of their forefathers, modified only by the new 

 materials they met with. By minute observations of 

 the Indians of the Amazon Valley, Mr. Bates arrived 

 at the conclusion that they were comparatively recent 

 immigrants from a colder climate. He says : " No 

 one could live long among the Indians of the Upper 

 Amazon without being struck with their constitutional 

 dislike to the heat. . . Their skin is hot to the touch, 

 and they perspire little. . . They are restless and 

 discontented in hot, dry weather, but cheerful on cool 

 days, when the rain is pouring down their naked 

 backs." And, after giving many other details, he 

 concludes, " How different all this is with the Negro, 

 the true child of tropical climes ! The impression gra- 

 dually forced itself on my mind that the Red Indian 

 lives as an immigrant or stranger in these hot regions, 



