Bokhara
to Persia or to other quarters, loses its peculiar fleece.[233] In all such
cases, however, it may be that a change of any kind in the conditions of
life causes variability and consequent loss of character, and not that
certain conditions are necessary for the development of certain characters.

Great heat, however, seems to act directly on the fleece: several accounts
have been published of the change which sheep imported from Europe undergo
in the West Indies. Dr. Nicholson of Antigua informs me that, after the
third generation, the wool disappears from the whole body, except over the
loins; and the animal then appears like a goat with a dirty door-mat on its
back. A similar change is said to take place on the west coast of
Africa.[234] On the other hand, many wool-bearing sheep live on the hot
plains of India. Roulin asserts that in the lower and heated valleys of the
Cordillera, if the lambs are sheared as soon as the wool has grown to a
certain thickness, all goes on afterwards as usual; but if not sheared, the
wool detaches itself in flakes, and short shining hair like that {99} on a
goat is produced ever afterwards. This curious result seems merely to be an
exaggerated tendency natural to the Merino breed, for as a great authority,
namely, Lord Somerville, remarks, "the wool of our Merino sheep after
shear-time is hard and coarse to such a degree as to render it almost
impossible to suppose that the same animal could bear wool so opposite in
quality, compared to that which has been clipped from it: as the cold
weather advances, the fleeces recover their soft quality." As in sheep of
all breeds the fleece naturally consists of longer and coarser hair
covering shorter and softer wool, the change which it often undergoes in
hot climates is probably merely a case of unequal development; for even
with those sheep which like goats are covered with hair, a small quantity
of underlying wool may always be found.[235] In the wild mountain-sheep
(_Ovis montana_) of North America there is an annual analogous change of
coat; "the wool begins to drop out in early spring, leaving in its place a
coat of hair resembling that of the elk, a change of pelage quite different
in character from the ordinary thickening of the coat or hair, common to
all furred animals in winter,--for instance, in the horse, the cow, &c.,
which shed their winter coat in the spring."[236]

A slight difference in climate or pasture sometimes slight