280 Colour and the Struggle for Life 



We found the example in the summer of 1880 or 1881 at Beaufort, 

 N.C., where the Johns Hopkins laboratory was located for the time 

 being. It must have been seen by many others, before or since. 



"I wrote and sent to Darwin a short description of the case at the 

 suggestion of Brooks, with whom I was at the time a student. I was, 

 of course, entirely unknown to Darwin (or to anyone else) and to me 

 the principal interest of Darwin's letter is the evidence that it gives 

 of his extraordinary kindness and friendliness towards an obscure 

 youngster who had of course absolutely no claim upon his time or 

 attention. The little incident made an indelible impression upon my 

 memory and taught me a lesson that was worth learning." 



Variable Protective Resemblance. 



The wonderful power of rapid colour adjustment possessed by the 

 cuttle-fish was observed by Darwin in 1832 at St Jago, Cape de Verd 

 Islands, the first place visited during the voyage of the Beagle. 

 From Rio he wrote to Henslow, giving the following account of his 

 observations, May 18, 1832: "I took several specimens of an Octopus 

 v>'hich possessed a most marvellous power of changing its colours, 

 equalling any chameleon, and evidently accommodating the changes 

 to the colour of the ground Avhich it passed over. Yellowish green, 

 dark bro^vn, and red, were the prevailing colours ; this fact appears 

 to be new, as far as I can find out\" 



Darwin was well aware of the power of individual colour ad- 

 justment, now knoAvn to be possessed by large numbers of Lepi- 

 dopterous pupae and larvae. An excellent example was brought 

 to his notice by C. V. Riley ^ while the most striking of the early 

 results obtained with the pupae of butterflies — those of Mrs M. E. 

 Barber upon Papilio nireus — was communicated by him to the 

 Entomological Society of London^. 



It is also necessary to direct attention to C. W. Beebe's* recent 

 discovery that the pigmentation of the plumage of certain birds is 

 increased by confinement in a superhumid atmosphere. In Scarda- 

 fella hica, on which the most comi)lete series of experiments was 

 made, the changes took place only at the moults, whether normal and 

 annual or artificially induced at shorter periods. There was a corre- 

 sponding increase in the choroidal pigment of tlie eye. At a certain 



^ Life and Letters, i. pp. 235, 236. See also Darwin's Journal of Researches, 1876, 

 pp. 6 — 8, where a far more detailed account is given together with a reference to Encycl. of 

 Anat. and Physiol. 



- More Letters, n. pp. 385, 886. 



* Trans. Eat. Soc. Lond. 1874, p. 519. See also More Letters, u. p. 403. 



* Zoologica: N.Y. Zool. Soc. Vol. i. No. 1, Sept. 25, 1907: Geographic variation in 

 birds with especial reference to the effects of humidity. 



