374 MY LIFE [Chap. 



" I know not how, or to whom, to express fully my 

 admiration of Darwin's book. To him it would seem 

 flattery, to others self-praise ; but I do honestly believe 

 that with however much patience I had worked and 

 experimented on the subject, I could never have approached 

 the completeness of his book, its vast accumulation of 

 evidence, its overwhelming argument, and its admirable 

 tone and spirit. I really feel thankful that it has not been 

 left to me to give the theory to the world. Mr. Darwin 

 has created a new science and a new philosophy ; and I 

 believe that never has such a complete illustration of a 

 new branch of human knowledge been due to the labours 

 and researches of a single man. Never have such vast 

 masses of widely scattered and hitherto quite unconnected 

 facts been combined into a system and brought to bear 

 upon the establishment of such a grand and new and simple 

 philosophy. 



" I am surprised at your joining the north and south 

 banks of the lower Amazon into one region. Did you not 

 find a sufficiency of distinct species at Obydos and Barra 

 to separate them from Villa Nova and Santarem ? I am 

 now convinced that insects, on the whole, do not give such 

 true indications of zoological geography as birds and mam- 

 mals, because, first, they have such immensely greater means 

 of dispersal across rivers and seas ; second, because they are 

 so much more influenced by surrounding circumstances ; and 

 third, because the species seem to change more quickly, and 

 therefore disguise a comparatively recent identity. Thus 

 the insects of adjacent regions, though originally distinct, may 

 become rapidly amalgamated, or portions of the same region 

 may come to be inhabited by very distinct insect-faunas 

 owing to differences of soil, climate, etc. This is strikingly 

 shown here, where the insect-fauna from Malacca to New 

 Guinea has a very large amount of characteristic uniformity, 

 while Australia, from its distinct climate and vegetation, 

 shows a wide difference. I am inclined to think, therefore, 

 that a preliminary study of, first, the mammals, and then the 

 birds, is indispensable to a correct understanding of the 



