SCIENCE-GOSSIP. 



65 



Say, for example, that cell a is in close relation to 

 a nerve, and cell b is away from the nerve but in 

 close apposition to cell a. Probably there are 

 bridges of protoplasm between the cells. If there 

 is a change in the nerve it results not only in a 

 modification of cell a, but of cell b also. To go 

 back again to hair. If we are to believe that 

 under strong mental excitement the hair suddenly 

 turns white, then it could be explained in a similar 

 manner to the above. 



In conclusion, it seems to me that both the 

 whitening of hairs and of feathers is the result of 

 a change in the trophic centres, brought about in 

 some cases by a normal condition, in some cases 

 by normal cause acting at a wrong time, and in 

 other cases by an abnormal condition. 



University Union, Edinburgh ; 

 April, 6th, 1895. 



The interesting article on "Pseudo-albino Spar- 

 rows," by Mr. K. Hurlstone Jones, opens a large 

 field for research and discussion, and although I feel 

 myself completely incapable of dealing fully with 

 the subject, there are a few remarks I should like 

 to add in answer to the question " are pseudo- 

 albinos born pseudo-albinos ? " In some instances 

 I should say yes, but not in every case. Last year I 

 obtained in May a curious variety of a young rook, 

 Corvus frugilegus {vide Science-Gossip, N. S., vol. i., 

 page 106), having five white primary feathers in each 

 wing, the base of the bill and the throat white, also 

 white claws and partly white toes. Two others, 

 with a suspicion of white about the throat and 

 white claws, I also shot in the same rookery, and I 

 should say were evidently birds of the same nest. 

 How these extremities, for it was the extremities in 

 every case, became white I am unable to say, but I 

 am inclined to Mr. E. L. Layard's suggestion in 

 your last issue of Science-Gossip, and put it down 

 to impaired vitality. 



Passing on to the question " If pseudo-albino 

 varieties have changed at some period of their exis- 

 tence later than their fledging, how do they get rid 

 of the melanin granules from their feathers?" 

 Surely, it appears to me, either by the same process 

 as the plumage of the immature gull changes, or 

 else from the reason I suggest presently. No one 

 seeing a herring gull (Larus argentatus) of the 

 second year when it is " mottled brown " would 

 imagine it would turn in the fifth year to the hand- 

 some grey and white bird it eventually does. It is 

 some accident possibly that changes to white the 

 typical feather of the sparrow, but I imagine the 

 change takes place during the time the old feather 

 falls out and the new one grows. There may be no 

 circulation in the shaft of the feather. I take Mr. 

 Hurlstone Jones's word for it that there is none, 

 for I have not studied the question ; but during the 



process of the feather developing in the quill- 

 sheath there is always a store of blood at the root. 

 You have only to pluck a growing feather from a 

 bird and squeeze it to ascertain this fact. This 

 being so, does it not seem possible that by some 

 means or other, such as want of vitality or an acci- 

 dent, this well, if I may so term it, dries up, and 

 therefore the result is the white plume. It is to be 

 observed that often blackbirds get a few white 

 feathers, more especially to the outer primary 

 feathers, the primary and median coverts, and the 

 bastard wing. I know of a tame blackbird that 

 gets a few more white feathers every time it moults. 

 It is an old bird, not far short of ten years, and I 

 think it is highly probable its vitality is enfeebled 

 and its blood-wells are drying up. Its legs are 

 quite a curiosity and look as if they had never 

 been " scaled." Sparrows, of course, one often 

 sees with white feathers, sometimes with only one 

 or two, and sometimes with many. One sparrow I 

 got last autumn had been seen about all through 

 the summer, but then had not as many white 

 feathers as when shot about the end of its seasonal 

 moult. There is another about the roads here now 

 that boasts of one solitary white feather in its tail, 

 and I am hoping it will be spared till next autumn 

 to ascertain whether the white feather will have 

 been replaced by a type form. 



The tendency seems to be to increased albinism 

 with each moult, but I see no reason for assuming 

 that this should always be the case. In fact, the 

 late Rev. F. O. Morris, in Vol. hi., page 83, of his 

 " British Birds," mentions a blackbird that in the 

 sixth year obtained white feathers in the wing, in 

 the following year reverted back to the typical 

 form again, and he also mentions (page 139) two 

 robins which were white the first year, changing to 

 normal colour the second season. It is possible 

 that in every case of pseudo-albinism, the effect of 

 the accident or injury or fright that has caused the 

 blood-wells to become dry, is capable of being 

 removed after a certain time and a normally 

 healthy condition return, but it is hard to deter- 

 mine this in a state of nature, whilst captivity 

 might have the opposite effect. It seems to me 

 that it is obvious that the blood influence bears 

 vastly upon the growing feathers. One has only to 

 take the canary for example. Red pepper feeding 

 before and at the time of moult will, as every 

 canary fancier knows, produce orange-coloured 

 birds. It is just the same with bullfinches — in 

 order to keep up the colouring of the breast, arti- 

 ficial feeding has to be resorted to for show pur- 

 poses, and the dark oily red-brown pepper paste is 

 given to the little captive. Thus it would appear 

 that blood influence, or rather no-blood influence, 

 bears considerably upon the theory of pseudo- 

 albinism. 



37, Nunnery Fields, Canterbury; April 3rd, 1895. 



