126 THE VALUE OF COLOUR 



Review l and an account of it is to be found in the 

 Origin- and in the Descent of Man. 3 



Darwin continually writes of the value of 

 hypothesis as the inspiration of inquiry. We find 

 an example in his letter to Bates, Nov. 22, 1860: 

 ' I have an old belief that a good observer really 

 means a good theorist, and I fully expect to find 

 your observations most valuable.' 4 Darwin's 

 letter refers to many problems upon which Bates 

 had theorized and observed, but as regards 

 Mimicry itself, the hypothesis was thought out 

 after his return home from the Amazons, when 

 he no longer had the opportunity of testing it by 

 the observation of living Nature. It is by no 

 means improbable that, had he been able to apply 

 this test, Bates would have recognized that his 

 division of butterfly resemblances into two 

 classes one due to the theory of Mimicry, the 

 other to the influence of local conditions could 

 not be sustained. 



Fritz Miiller's contributions to the problem of 

 Mimicry were all made in S.E. Brazil, and 

 numbers of them were communicated, with other 

 observations on natural history, to Darwin, and 

 by him sent to Professor R. Meldola who 

 published many of the facts. Darwin's letters to 

 Meldola 5 contain abundant proofs of his interest 

 in Miiller's work upon Mimicry. One deeply 



1 New Ser., iii. 1863, 219. a Ed. 1872, 375-8. 



3 Ed. 1874, 323-5. 4 More Letters, L 176. 



6 Poulton, Charles Darwin and the theory of Natural Selection, 

 Lond. (1896), 199-218. 



