28 PROPERTIES OF WOOL. 



composed almost entirely of gelatine, so that although it may 

 be dissolved by much boiling, it is insoluble in water at the 

 common temperature. 



It is well known the skin of the sheep is seldom fully 

 tanned, but is prepared in a peculiar way, and used for the 

 common sort of binding for books, or is converted into parch- 

 ment, which, from its durable nature, is used for the inscrip- 

 tion of documents of more than ordinary value. Other uses 

 made of the pelts of lambs in foreign countries, mention will 

 be made hereafter. 



ANATOMY OF WOOL. 



Although the fibre of wool has been submitted to seveic 

 examinations of powerful microscopes, its internal structure 

 is not yet definitely settled — whether solid, or conisting of a 

 hard exterior tube with a pith within. The weight of testi- 

 mony, however, is much in favor of the supposition o"f the 

 latter. The fact may be adduced in support of this conclu- 

 sion, that the wool of the sheep, when in high condition, is 

 coarser than when in low flesh, the fibre being distended 

 apparf xitly from no other cause than the superabundance of 

 the secretive matter designed for its growth. Could it be 

 otherwise were it not tubular in its conformation 1 It may, 

 however, proceed from another cause, for- it has been satis- 

 factorily ascertained that the fibre is vascular, being supplied 

 with vessels which convey nourishment from the pulp, 

 which seem to accompany it to a considerable distance 

 from the root, if not through its whole extent. 



The learned Dr. Good says : — " The Plica polonica, a 

 disease whose existence is doubted by some, but of the oc- 

 casional occurrence of which there is abundant testimony, 

 completely establishes the vascularity of the hair ; -for it is 

 an enlargement of the individual hairs, so much so as, in 

 some cases, to permit the passage of red blood, for the hair 

 will bleed when divided by the scissors." Admitting it to 

 be true that the hair is vascular, it follows that the fibre of 

 wool is also ; and hence if a sheep is in more than ordinary 

 condition, the consequent -repletion of the fluids would cause 

 an increased bulk of the fibre, without the necessity of a 

 tubular conformation. But leave is taken of the question, 

 with thQ repetition that the preponderance of testimony is 

 in favor of the theory that the fibre is hollow. 



Each fibre of wool is composed of a number of filaments 



