ZOOLOGY. 301 



throat of this bird, from the bill down to the breast, was pure white, over 

 the breast ran three bands, blue, black, and yellow, the black one being the 

 narrowest. In the middle of February, the blue band became darker, and 

 spots of the same color appeared all over the white throat, with the excep- 

 tion of a small spot in the centre. On the 21st of February, all the throat 

 was blue except that spot, which remained pure white till the 23d, when it 

 became reddish. On and after the 24th, this reddish color also changed to 

 blue; but on the 1st of March there appeared again, in the midst of this 

 blue, a lighter spot of beautiful silvery appearance; and it is worth remark- 

 ing, that this new. color began at the basis of the feather, and proceeded 

 outwards. Meanwhile, the black band on the breast had become larger, and 

 shaded insensibly into the blue, while the yellow band remained unchanged 

 through all these mutations. Thus the bird had got its wedding plumage, 

 without losing one feather, and this it kept through all the reproductive season. 

 At the same time, Dr. Gloger, of Berlin, showed that a very similar obser- 

 vation had been previously made in this country by Audubon, on a male 

 gull, which changed the color of its head, in a fortnight, from gray to the 

 purest black, and, as he supposed, without changing a feather. 



There can be no longer any doubt about the fact; but the question is, how 

 can a feather change its color, when its blood-vessels and nerves are dried 

 and dead, as is the case with every feather soon after it has reached its full 

 growth. Dr. Weiuland had only heard of one explanation, viz., that the 

 wearing away of the tine laminae of the veins of the feather, the so-called 

 pinnulae, might produce the change of color. This seemed to him not only 

 an unpln^siological view of the subject, that a bird should get its wedding plu- 

 mage by such a kind of decay of the feather, but, in the cases which he had 

 observed, the changed feathers showed no traces of such a wearing process. 

 The following explanation of the fact seemed to him the most natural : 



Conservators of museums very frequently notice that certain birds in the 

 collections bleach, particularly when exposed to light. A red-breasted Mer- 

 ganser (Meryus mei-yaiisa-) which Dr. Weinland saw, when just shot, with a 

 red breast, and which, after having been deposited in the museum for some 

 time, presented a pale whitish breast, showed this very remarkably. He 

 afterward obtained a bird of the same kind, and, when fresh, examined its 

 breast-feathers with a high power of the microscope, and found all the pin- 

 nulae tilled in spots with lacunes of a reddish fluid, which, from the dark 

 appearance of their margins, seemed to be of an oily character. Some 

 weeks afterwards the same feathers, having been exposed to the light, had 

 become nearly white, and he found in the pinnulse, instead of the reddish 

 lacunes, only air-bubbles, which it is known produce a white color, as in the 

 case of the lily, which is rendered white by the air in its cells. This obser- 

 \ation led him to the conclusion, that in this case the evaporation of the 

 reddish fluid, and the filling of the spaces with air, produce the change of 

 color. If this fluid is an oily matter, as there is reason to suppose, it will be 

 readily admitted, physiologically, that it may be furnished by the organism, 

 by imbibition through the tissues, in consequence of a certain disposition of 

 the nerves leading to the skin and to the sac of the feather in the skin, 

 (even if the vessels and the nerve in the feather itself should be dried), for 

 fat goes through all tissues without resistance, and also through horn. 

 Thus the fat coloring matter may flow out into the feathers during the time 

 of reproduction, which is the richest season in every living organism; and 

 then again, from want of food, cold temperature, weakness, decrepitude, 



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