TEXTILE FIBRES

Animal fibres are of two cla es, the most important containing hair and its varieties, growths originating in the outer skin or epidermis and forming the natural coverings of mammalian animals. Most valued and most widely used of these is wool, such as that of the many breeds of domestic sheep, Cashmere, alpaca, and vicuna goats. Wool varies in length, texture, and felting properties, the last on the development of depending microscopic ridges characteristic of such fibres. Hair, such as that of camels, 4s also much used. The second cla animal secretions, the most contains important being the silk fibres spun into a cocoon by the larva of the silkworm moth (Bumbyz). Useful plant fibres consist of elongated complex fibrovascular bundles from the stems of such plants as flax, jute, and hemp, or of the simpler hairs protect the seeds of such as the which cotton eee es a In general quality anima res are wished from vegetab le fibres by Sistine non-conducting propert ies the greater former—their greater power of of the and excluding warmth. The] retaining are nitrogenous in nature, the| former are composed of a carbohy dratelatter cellulose. simple discriminating test is that A fire—animal fibres frizzling with a of horny odor, without smell. More delicate is that of boiling in a weak solution of caustic soda in water, wherein animal fibres di olve while vegetable fibres remain. Microscopic structure also furnishes a sure guide to the nature of fibres.