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barbules; but these do not occur in the ostrich, hence the looseness of 
the flue. 
4a. Double-Floss.—The name “ double-floss” applied to some feathers 
should really be “ double-flue.”” In these the barbs come off so closely 
from the shaft that they alternate with one another instead of being in 
a single row down each side; this gives a double appearance to the flue, 
and signifies great density, which is much desired. 
5. Barbs.—These are the separate parts of the flue which are directly 
connected with the shaft, and extend from it either horizontally or 
obliquely upwards. According to their strength they determine whether 
the flue is.“ self-supporting ”’ or not. 
6. Barbules.—The barbules are the short, fine. delicate parts of the 
flue which arise from each side of the barbs, from which they are split off 
just as the barbs. are split off from the shaft. The barbules vary much in 
length in the different qualities of feathers and greatly determine the 
density. By some farmers the term flue seems to be used so as to include 
cnly the barbules and not the barbs, and by others to mean only the barbs. 
7. Plwme.—It is recommended that the term plume be restricted so 
as to mean only the part of the feather above the quill, that is, the part 
of the feather which is clipped. the quill being the part remaining behind’ 
. to be drawn when ripe. In practice a short portion of the quill is clipped 
along with the plume so as to enable the plumes to be handled and tied 
together without damaging the flue. Thus restricted a plume would in- 
clude the shaft and the flue. but not the quill; feather would include the 
whole, that is. both plume and quill. 
8. Pith or Medulla.—This is the soft central part of a “ green” 
feather in which flows the blood which nourishes the growing feather. If 
a plume is cut “green.” the pith can often be drawn out of it as a soft, 
narrow, worm-like thread, red with the blood. while severe bleeding or 
hemorrhage takes place from the end of the part remaining in the socket. 
As the feather grows the blood slowly recedes downwards and completely 
disappears, and then the pith dries up and the space it occupied becomes 
filled with air. As the feather expands a horny sheath which surrounded 
the pith is to be seen on the inner or grooved side of the shaft enclosing a 
number of thin horny cones fitting over one another and often containing 
dried blood. This horny pith sheath extends the whole length of the 
plume, but is preened away by the bird as the feather opens out in the 
course of its growth. Within the transparent ripe quill shorter ‘ feather- 
cones’ can be seen. The cones are the partitions which successively cut 
off the nutritive blood from above as the feather grows in length and 
matures. 
It is of some importance to know that the red blood never leaves the 
pith or medulla to pass to the feather substance proper; so that the 
feather itself never has any blood in it, but only surrounds the blood flow- 
ing in the medulla. Only the colourless liquid part of the blood’, the 
blood-plasma, exudes through the sheath of the pith and nourishes the 
growing feather. The nerves and blood-vessels are restricted to the 
medulla, which is really a part of the under skin prolonged into the 
, feather and carrying blood-vessels and nerves. The feather having neither 
nerves nor blood-vessels there is no pain nor bleeding when the pipe feather 
is clipped, anymore than when our own hair is cut. 
2. Superior or Upper Umbilicus.—The upper umbilicus is a small 
aperture in the feather on the inner side where the plume and the quill 
meet. It represents the place at which the pith or medulla emerges from 
the quill to pass up the shaft. ; 
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