Feather
a plume or quill, one of the dermal growths, multitudes of which constitute the covering of a bird. A feather is homologous with a hair from the skin of a mammal, and some of the inferior birds have imperfect feathers suggestive of hairs only. A feather consists (a) of a central shaft, which is tubular at the base. This is inserted in the skin like a plant in the earth, living and growing. (b) Of a web on either side, that on one side being often developed more than on the other other. This web oped is composed of a series of regularly arranged fibers, called barbs. In some cases, of a small supplementary shaft with barbs, called the plumule-i. e., the little plume. Feathers are of two kinds, quills on the wings and tail, and plumes generally diffused. The primary feathers rise from the bone corresponding to the hand in mammals; the secondary feathers from the distal end of the forearm; and the tertiary feathers from the proximal end of the forearm. The feathers are renewed once or twice a year; the bird is languid during the process, but, when fresh plumage is obtained, renews its youth in vigor as well as in beauty.
The beard and quill of feathers have essentially the same composition, about FEBRIFUGE 52.5 per cent carbon, 7.2 hydrogen, 17.9 nitrogen, and 22.4 oxygen and sulphur.
Feathers owe their permanent color to peculiar pigments, of which the red, green, lilac, and yellow are soluble in alcohol and ether. Black feathers contain a pigment insoluble in alcohol and ether, but soluble in ammonia.