(wasBni) 
Nore on THE INFLUENCE OF A TroricaL CLIMATE ON THE WOOL OF 
THE SHEEP. 
By Joun Davy, M.D., F.R.S., L. & E., &ce. 
(Ed. New Phil. Journal.) 
Tue sheep of Barbadoes, originally from an English stock, affords a 
striking example of the change that may be effected by climate, in a few 
generations, in the character of the hair of an animal. In that Island 
instances are frequently to be seen of sheep in which hair has so taken 
the place of wool (using the terms in their usual acceptation), that were it 
not for the form of the animals,—.and that is not altogether free from change, 
it would be impossible to suppose that they belonged to the same species 
as our English sheep. 
Considering the subject of such a change not undeserving of attention, 
I have examined two specimens of hair procured for the purpose, one from 
a sheep two years old, the other from one about a year old, which were 
obligingly sent me, at my request, by a friend, a resident. 
Both were nearly of the same colour, a light reddish-brown, and were 
nearly of the same length, that is, the individual hairs,—varying from 
about an inch to an inch and a-half. The hair of the three-year old was 
coarser than that of the one-year old; it consisted chiefly of harsh fibres 
slightly tortuous, each about 180th of an inch in diameter,—some cylin- 
drical, others more or less flattened, all tapering towards a point at their 
distal extremity. The hair of the one-year old consisted of coarse and fine 
fibres in about equal portions; the one about 363d of an inch in diameter, 
the other about 1333d of an inch; the former resembling the hair of the 
older sheep, the latter having the appearance of wool, and that both in its 
fineness and general aspect, whether seen with the naked eye or under the 
microscope. The presence of a portion of wool mixed with the hair of 
the younger sheep accords, I may remark, with the belief of my friend by 
whom the samples had been sent, viz., “ that all the very young lambs of 
the island have wool, which gradually pass into hair as they grow older.” 
This, he writes, he thinks is the fact, though he cannot say positively 
that it is so, not having attended sufficiently to the subject. 
Interesting in itself, as exemplifying how Nature fits an animal, the 
native of a cold climate, by a change in its clothing, to endure without 
discomfort the heats of a tropical region it is not, as it appears to me, with- 
out value in its analogical applications. 
Though so much changed in appearance as is the wool in passing into 
hair, the one differs as little from the other in intimate structure as the hair 
of the woolly-headed African does from the straight, lank hair of the North 
