124 
COMPARATIVE ANATOMY. 
design, that wool in hot countries, degenerates, as it is 
called, but in truth (most happily for the animal’s ease) 
passes into hair; whilst, on the contrary, that hair on the 
dogs of the polar regions, is turned into wool, or some¬ 
thing very like it. To which may be referred, what natural¬ 
ists have remarked, that bears, wolves, foxes, hares, which 
do not take the water, have the fur much thicker on the 
back than the belly: whereas in the beaver it is the thick¬ 
est upon the belly; as are the feathers on waterfowl. 
We know the final cause of all this; and we know no 
other. 
The covering of birds cannot escape the most vulgar ob¬ 
servation. Its lightness, its smoothness, its warmth;—the 
disposition of the feathers all inclined backward, the down 
about their stem, the overlapping of their tips, their differ¬ 
ent configuration in different parts, not to mention the va¬ 
riety of their colors, constitute a vestment for the body, 
so beautiful, and so appropriate to the life which the animal 
is to lead, as that, I think, we should have had no concep¬ 
tion of anything equally perfect, if we had never seen it, 
or can now imagine anything more so. Let us suppose 
(what is possible only in supposition) a person who had 
never seen a bird, to be presented with a plucked pheasant, 
and bid to set his wits to work, how to contrive for it a 
covering which shall unite the qualities of warmth, levity, 
and least resistance to the air, and the highest degree of 
each; giving it also as much of beauty and ornament as 
he could afford. He is the person to behold the work of 
the Deity, in this part of his creation, with the sentiments 
which are due to it. 
The commendation, which the general aspect of the 
feathered world seldom fails of exciting, will be increased 
by farther examination. It is one of those cases in which 
the philosopher has more to admire than the common ob¬ 
server. Every feather is a mechanical wonder. If we 
look at the quill, we find properties not easily brought 
together,—strength and lightness. I know few things 
more remarkable than the strength and lightness of the 
very pen with which I am writing. If we cast our eye 
to the upper part of the stem, we see a material, made for 
the purpose, used in no other class of animals, and in no 
other part of birds; tough, light, pliant, elastic. The 
pith, also, which feeds the feathers, is, amongst animal 
substances, sui generis: neither bone, flesh, membrane, 
nor tendon. 
But the artificial part of a feather is the beard, or, as it 
