Influence of Climate, S)'c., on Sheep. 
103 
trace every intermediate stage from this condition to the finest 
qualities of wool. Zornlin gives the following interesting illus- 
tration of this change from wool to hair : — 
" As ;in instance we may nienliou that the fleece of the sheep is liable to 
variations according to the temperature of the region in which it is placed. 
The shee[) originally transported to the New World was a variety with coarse 
roujih wool. A remarkable cluiiise is observable in the fleece of the race 
(de.-cended from those sheej)) which now inhabits some of the warm valleys of 
South America. The lambs possess the woolly fleece, but if left unshorn this 
coarse wool falls off and leaves a short glossy and compact hair. In some 
parts of tlio same region the cows also, instead of having rough hair similar to 
that of horned cattle of temperate zones, have tlieir skins as bare as the 
Barbary dog.'' 
There is nothing therefore in the structure of our sheep which 
necessarily renders them wool-bearing animals, independent of 
the circumstances under which they are placed. Hair and wool 
are both produced from very minute vascular bulbs situated 
beneath the epidermis or outer skin : these, on examination, have 
the appearance of a number of holes, but are really so many 
tubes passing through the skin and terminating in small bulbs 
or follicles, in and around which nourishment is supplied by 
means of the blood vessels. In these follicles there is no essential 
difference whether wool or hair be produced; the result is solely 
determined by the circumstances and conditions of life. Rapidity 
of growth is primarily dependent upon the nutriment conveyed 
to these bulbs. If an animal be fed liberally the blood becomes 
enriched thereby, and every part of the body participates in the 
store of nutriment distributed throughout the system. A liberal 
dietary therefore tends to promote, and poor scanty food to 
check, the growth of wool. Moreover, the even growth of wool 
depends upon the animal being regularly supplied with food; 
and unevenness in wool is accompanied by a tendency to break 
at that portion of the fibre which was produced whilst the 
animal was feeding on inferior food. Mountain sheep are very 
subject to such changes, from plenty to scarcity, with all the 
attendant evil consequences ; but the discredit of this should fall 
on the flock-owner rather than on the flock. The growth of 
wool is further influenced by the state of the skin, which in a 
well fed sheep is soft and oily to the touch, and has a tendency 
to encourage a softness of wool which is most desirable. 
The size or fineness of wool is in a similar, manner influ- 
enced by that of the pores of the skin through which it has to 
pass. In warm weather the pores are more open and the wool is 
of a stronger character than when the pores are contracted by 
the cold. To equalise the size of the fibre any extreme of heat 
on the one hand, or of cold on the other, ought as much as pos- 
sible to be avoided. This is another cause of the unequal 
