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CHAPTER XI.

EPIDERMIC PRODUCTS.

, T'HE produdls of the epidermis, the hair, nails, horn, wool, the scales ofsome of the lower animals, skin, feathers, are all, chemically, the samesubstance, but in a different state of aggregation. They are insoluble inwater, alcohol, and acetic acid. Solutions of caustic alkalies cause thesesubstances to increase in bulk at the ordinary temperature of the air, butno real solution takes place; on being boiled with alkaline lyes, solutionsimultaneously with decomposition sets in, ammonia being evolved. Thesubstances contain from 2 to 3 per cent of sulphur. Submitted to the adtionof water boiling under pressure, in a Papin’s digester, they dissolve withdifficulty, yielding solutions which do not gelatinise, a characteristic dis-tinguished from that of the organic tissue of bones, cartilage, and theepidermis. The most interesting of these epidermic products is wool.

Wool.

This is a peculiar filamentous material secreted by the skin of sheep and ofsome varieties of goats. The use of wool for spinning and weaving is of sohigh an antiquity that it is impossible to say where and with whom itoriginated, but wool was undoubtedly in use long before vegetable fibreswere employed. The cause of this early application is obvious when weconsider that wool possesses fineness, flexibility, and elasticity of fibre notmet with in an equal degree in any vegetable fibres. Further, wool is naturallyeither white, yellow, or brown in colour, and can be more readily bleached,.while it assumes dyes more easily than vegetable fibre. The Commissionersappointed to inquire into the best means of preventing the pollution of rivers(Rivers Aire and Calder), say, speaking of the woollen trade :—“This trade isof ancient date in England. The Romans had weaving establishments ofwoollen cloth at Winchester, where the copious springs from chalk affordedmeans both for power and for washing and dyeing. The mother of Alfredthe Great is recorded to have been skilled in spinning wool. Flemish woollenweavers settled in England about the time of the Norman Conquest, and acontinued immigration of woollen weavers from Flanders took place in thereigns of Henry I., Henry III., Edward I. and III. The woollen tissues firstspun and woven at Worsted, in Norfolk, about the year 1388, became thestaple trade of Norwich. Devonshire manufactured woollens soon after theintroduction of the trade into England, and Worcestershire a little later.Friezes were also early manufadtured in Wales. In the middle of the 16thcentury Berkshire took the lead in woollen manufadture. About themiddle of the last century the West Riding of Yorkshire became the seat of