Darwin's Advice 65 



urged me to keep separate portfolios relating to the various 

 heads of the subject I was studying, one for " Geographical 

 Distribution," another for " Moult," " Migration," etc., and 

 into these portfolios were to be cast the memoranda and 

 references relating to each subject as I came across the 

 facts. When the portfolios grew bulky in course of time, 

 it would then be seen whether the accumulated material 

 was sufficient to be arranged in order, and the results 

 published to the world. This Darwinian method of work, 

 which he informed me was the one adopted by himself, 

 seems to me to be an admirable plan not only for scientific 

 workers, but for all those engaged in the study of any 

 difficult subject. It was also a great privilege in my early 

 days to possess the friendship of Dr. Alfred Russel Wallace, 

 who was always ready to help me with his notes and 

 experiences of bird-life on the Amazon and in the Eastern 

 Archipelago. Without the loan of the specimens in his 

 collection, it would have been impossible to have completed 

 my Monograph of the Kingfishers. 



Of the process of development from one form to another 

 we can but form a guess, but there are one or two instances 

 which occur to me which may be briefly noticed as of 

 some interest. To take the family Ncctaniiidce or Sun- 

 birds, for example. These little birds inhabit the tropical 

 portions of the Old World, and are found throughout 

 Africa and India; thence the)- occur eastwards to Southern 

 China, and southwards to the Malay Archipelago and 

 Northern Australia. In their metallic plumage, extensile 

 tongue, and even to a certain extent in their habits, they 

 resemble the Humming-birds [Trocliili) of America, but the 

 resemblance is merely superficial, and the two Families have 

 little in common with each other as far as structure and 

 affinity are concerned. The Humming-birds are Ficarian, 

 their relations being with the Swifts {Cvpscli), while the 

 Sun-birds are thoroughly Passerine birds and not unlike Tits 



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