u)hI Culour-rhunye ui Birds. -109 



Let us now turn for a moment to see what evidence can 

 be found on the other side of the question. 



The cliief argument is that it is anatomically impossible ; 

 that a feather once formed has no longer any connection 

 with the blood-system, and is therefore technically a dead and 

 cast-off structure, and that consequently pigmei)t, which can 

 only be brought by the blood, cannot be conveyed to the 

 feather. I have already pointed out that experiments made 

 by others on the subject clearly prove that it is quite possible 

 for pigment deposited at the base of a feather to work its 

 way up by purely physical means. If an artificial pigment 

 can do this, we need have little doubt that it is possible for 

 a natural pigment to do the same. 



The two chief papers that have been written against colour- 

 change of recent years are those of Messrs. Allen and Stone "^. 

 I have read the former, which is a review of papers in favour 

 of colour-change, very carefully, and although here and 

 there the author points out slight discrepancies in the state- 

 ments made by other writers, he adduces no proofs in favour 

 of non-colour-change. But as it will perhaps be said that 

 the burden of proof rests with advocates of the change, I 

 will go further, and say that he does not disprove any of 

 the statements made in the papers criticised. To deny 

 statements flatly, or to cast them aside as "too obviously 

 absurd for serious consideration/' by no means disproves 

 them, but to my mind shows a certain amount of weakness, 

 for if there were any good arguments against the theory of 

 colour-change. Dr. Allen would surely have brought them 

 forward. 



I do not propose to deal at any length with these papers, 

 but would like to notice one or two examples of Dr. Allen's 

 contradictions. Criticising some notes made by a keeper at 

 the Zoological Gardens, who stated that the Ruff assumed the 

 summer-plumage on the body-feathers by change of colour, 

 Dr. Allen states : " The Ruff is thoroughly well known to 

 moult its body-plumage in spring."' Now I have kept Ruffs 

 in captivity and shot them wild, and, although 1 know that 

 * Loc. supra cit. 

 SER. VII. VOL. VI. 2k 



