[12] On the whole subject of Jewish festivals see Reland, Antiq. Hebr.; Knobel, Leviticus (c. 23); George, Die jüdischen Feste; Edersheim, The Temple; its Ministry and Services; Ewald, Altertümer des Volkes Israël; articles in Bible dictionaries.
[13] As, at a later period (601), Gregory the Great instructed his Anglo-Saxon missionaries so to Christianize the temples, festivals, &c., of the heathen “ut durae mentes gradibus vel passibus, non autem saltibus, eleventur.”
[14] Manumission, however, was lawful on any day.
FEATHER (O. Eng. fether, Ger. Feder, from an Indo-European root seen also in Gr. πτερόν, and πέτεσθαι, to fly), a horny outgrowth of the skin of birds homologous with the scale of the reptile. The body-covering of birds is, without exception, comprised of feathers, and by this character alone birds may be distinguished from all other animals.
The most perfect form of feather is made up of a long, tapering rod, fringed on either side, for the greater part of its length, by a secondary series of slender and tapering rods forming a more or less acute angle with the central axis. This fringe is known as the vexillum or “vane” (fig. 1 a). The central axis is divisible into two distinct parts,—a hollow, cylindrical, transparent calamus, or “quill,” the base of which is inserted into the skin, and a solid, quadrangular rhachis or “shaft” which supports the vane. At the lower end of the quill is a small hole—the lower umbilicus—through which the nutritive pulp passes during the growth of the feather: while at the upper end, where it passes into the shaft, a similar hole will be found,—the upper umbilicus—and from this the last remains of the capsules which contained the nutritive pulp may sometimes be seen protruding. If the quill is cut open a series of these capsules will be found fitting one into the other throughout the whole length of the tubular chamber.
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| Fig. 1.—Diagrams of Feather-Barbs. | |
a, Outline of a feather showingthe relation of the barbs andbarbules to the central axisor shaft. b, Section across two of the barbsshown in a, highly magnified. c, Two barbules of the posteriorseries—seen only in cross-sectionin b. | d, A barbule of the anterior series. e, Section across the base of threeanterior barbules showingattachment to barb. f, A portion of the hooklet of theanterior series showing themethod of interlocking withthe barbules of the posteriorseries. |
The rods comprising the lateral fringe, or vane, are known as the rami or the “barbs,” and will be found, on microscopic examination, to be lath-shaped and to taper to a point. Further, each barb supports a double series of smaller outgrowths known as the radii, or “barbules”; so that each barb may be likened to a feather in miniature. These “barbules,” however, differ markedly in structure on the two sides of the barb, those pointing towards the tip of the feather—the “anterior barbules”—being ribbon-shaped from the base outwards for about half their length, when they become cut up to form a series of long and very delicate hooklets (fig. 1 d). On the opposite side of the barb the barbules are also ribbon-shaped for about half their length, but the ribbon is curved trough-fashion, so that the whole series of posterior barbules forms a number of deep valleys, and into these the hooklets are thrust so as to catch hold of the upper edges of the troughs, which are set so that the upper edge is towards the upper, and the lower edge towards the under surface of the feather. The manner in which this beautiful mechanism works may be seen in fig. 1 b.
In one of the primary or “quill” feathers of the wing of a crane, each barb of the inner side of the vane was found to bear about 600 pairs of barbules, which would make about 800,000 barbules for the inner web of the vane alone, or more than a million for the whole feather (H.F. Gadow). It is to the agency of these hooklets alone that the closely-knit, elastic vanes of the flight feathers and the body feathers are due. Where these hooklets are wanting the barbs do not adhere together, resulting in a loose “discontinuous” vane such as, for example, is found in the plumes of the ostrich.
Many feathers, in addition to the main axis, bear a second, generally much shorter axis, supporting a loose discontinuous vane; this shorter branch is known as the “aftershaft” and arises from the under surface of the feather. Only in the cassowary and emu among adult birds is the aftershaft as large as the main shaft.