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. 
“T 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 
which possessed a most marvellous power of changing its colours, 
equalling any chameleon, and evidently accommodating the changes 
to the colour of the ground which it passed over. Yellowish green, 
dark brown, 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 known 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 inca, on which the most complete 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 the eye. Ata certain 
1 Life and Letters, 1. pp. 235, 236. See also Darwin’s Journal of Researches, 1876, 
pp. 6—8, where a far more detailed account is given together with # reference to Encycl. of 
Anat. and Physiol. 
2 More Letters, 1. pp. 385, 386. 
3 Trans. Ent. Soc. Lond. 1874, p. 519. See also More Letters, u. p. 403. 
+ Zoologica: N.Y. Zool. Soc. Vol. 1. No. 1, Sept. 25, 1907: Geographic variation in 
birds with especial reference to the effects of humidity. 
