Vegetable fibers are plant cells. Their structure is simple and they are largely made up of cellulose, with more or less foreign material, such as plant waxes, resins, etc. They are various parts of the plants, such as seed hairs, as cotton; stem fibers, as flax, hemp, jute, and ramie; leaf fibers, as Manila hemp and various species of aloe; or finally, they may be fruit fibers, as coir, or cocoanut fiber, which comes from the covering of the cocoanut fruit.

1 Matthews. Textile Fibres, p. 1.

The seed hairs are single-celled fibers, almost pure cellulose; the bast fibers, or those coming from the stem of the plants, are multicellular, and must be separated from the woody material in which they are imbedded.

Animal fibers are nitrogenous substances, protein, containing carbon, hydrogen, oxygen, nitrogen, and, in some cases, sulphur, phosphorus, and other mineral matters. They are either appendages to the skin of animals, as wool and the various hair fibers, or they are animal secretions, as silk and the secretion of various spiders, mollusks, etc.

The difference in structure of the individual fibers and classes of fibers, and the difference in chemical reactions, makes necessary very different methods in the treatment of these fibers in their manufacture into cloth.

In physical structure the fibers differ in length, diameter, strength, elasticity, color, luster, and microscopic characteristics.

Cotton is the shortest fiber, varying in length from one-half inch to two and one-half inches. Wool varies in length from one inch to seven or eight inches. Silk is a long fiber, being continuous for perhaps four hundred yards in the best cocoons, while linen usually is twelve to thirty-six inches in length. The diameter of the different fibers varies so that it is difficult to compare them; the finest, however, are found in silk and the coarsest in wool and flax. Silk is the strongest fiber, cotton and linen coming next in order. Silk and wool are most elastic, linen being least so. In color, cotton may be pure white or nearly yellow; wool varies from white to gray, brown and black being less common; linen, according to methods of treatment in separating the fiber from the stalks, is found in different shades of tan, brown, and gray. Silk varies from almost pure white to quite a deep yellow or tan. Again, silk has more luster than other fibers, and linen has more than cotton or wool. The luster of the different fibers may be increased by physical or chemical treatment. These different qualities readily show why silk is such a valuable fiber. Wool, because of its hygroscopic and non-conductive qualities, is excellent for clothing; cotton is cheap and to a certain extent may replace the others; while linen is valued chiefly for wearing quality and texture.

Wool and Cotton Fibers.

Fig. 14. Wool and Cotton Fibers.

Linen Fibers.

Fig. 15. Linen Fibers.

Microscopic Characteristics

With the aid of the microscope it is quite easy to distinguish one fiber from another: cotton by the spiral twist which the flat, ribbonlike fiber always has, wool by its scale-like surface, linen by apparent joints and crosswise markings, and silk by its structureless, transparent, lustrous surface.

Since a thorough understanding of the cloth made from these fibers requires a careful study of their characteristics, the method of manufacturing them into cloth, the adulterations, etc., a detailed account will be given of wool, cotton, linen, and silk. Brief mention may here be made of some of the minor fibers which are, however, found to quite a large extent on our markets.