PEEFACE. 



Ix the autumn of 1847 Mr. A. R. Wallace, who has 

 «ince acquired wide fame in connection with the Dar- 

 winian theory of Natural Selection, proposed to me a 

 joint expedition to the river Amazons, for the purpose 

 of exploring the Natural History of its banks ; the plan 

 being to make for ourselves a collection of objects, dis- 

 pose of the duplicates in London to pay expenses, and 

 gather facts, as Mr. Wallace expressed it in one of his 

 letters, "towards solving the problem of the origin of 

 species," a subject on which we had conversed and 

 corresponded much together. We met in London, early 

 in the following year, to study South American animals 

 and plants at the principal collections ; and in the 

 month of April, as related in the following nan-ative, 

 commenced our journey. 



My companion left the country at the end of four 

 years ; and, on arriving in England, published a naiTa- 

 tive of his voyage, under the title of " Travels on the 

 Amazons and Rio Negro." I remained seven years 

 longer, returning home in July, 1859 ; and having taken, 



VOL. I. b 



