Birds. 3669 



without being organized, or at least having but a very low degree of 

 vitality, they are connected in a somewhat similar manner to that of 

 the connexion of the teeth with the membrane of the gums, and so 

 remain till the time of moulting, when their attachment becomes loos- 

 ened, and at last they fall out, not, however, as I before said, until 

 they have led the feathers which are to succeed them into the cavities 

 they are about to vacate, in precisely the same way as the first plu- 

 mage had been brought through by the down with which the bird had 

 been first clad. 



Jf then the blackbird had assumed his mottled hue immediately af- 

 ter his fright, and the perfectly formed and dried feathers had become 

 white in lieu of their former black, I should have been at a much 

 greater loss to comprehend how the change was effected : but now, 

 seeing that he did not " show the white feather " till long after his 

 alarm had ceased, may not the germs of the feathers which at the 

 next moult appeared white, have been already sufficiently formed to 

 be at the root of the then existing feathers ? — and may not sudden 

 fright have so disarranged the natural and habitual functions of the 

 bird, as to have had the effect of withdrawing the colouring matter 

 from these incipient feathers, just as we know that a total loss of co- 

 lour has occasionally taken place on a sudden in the human hair, 

 from some violent mental excitement ? 



The more I reflect on this matter, the more am I strengthened in 

 my opinion that terror was the cause of the blackbird assuming his 

 mottled dress. Looking at the account of the formation of feathers 

 as detailed above from Malpighi and Cuvier, and the great analogy 

 existing therein between them and the hair of human beings, and not 

 forgetting the statement of Bishop Stanley that fright will produce the 

 same effect upon the plumage of birds as upon the hair of man ; tak- 

 ing into account at the same time the manifest signs of extreme terror 

 exhibited for days by the bird ; I cannot but conclude at present that 

 fright caused by the " crocking," as I before said, was the reason of 

 the blackbird becoming partially white. 



Of course, I would not for an instant be understood to say that I 

 consider fright to be the only cause of birds turning white or mottled. 

 I quite agree with Mr. Johnson, that the occurrence of white black- 

 birds, rooks, jackdaws, swallows, sparrows, larks, &c, is sufficiently 

 common ; I do not at all pretend to account for them, or any other 

 freaks of Nature, such as albino varieties, not only amongst birds 

 and quadrupeds, but even amongst the human race : neither would I 

 make fear (of cold) the acting cause of the assumption of a white 



