E. Schunck in his investigation of cotton bleaching (Chem. News, 17, p. 11) finds that in boiling with sodium carbonate solution the fibre loses 5 per cent. in weight. Some portion of the dissolved substances is precipitated on acidifying and is found to contain a wax, brown resinous and colouring matters, and pectic acid. {48} Forms in which employed.—Fibrous refuse from the decortication of the seeds; spinning waste, threads, rags, new and old. Class B. FLAX.—Genus, _Linum_. Order, _Linaceæ_, Bast fibres and filaments. Length of fibres, 25–30 mm.; diameter, 0·02 mm., ratio, 1200. Illustrated in Fig. 6: _a_, sections of the fibres, isolated and in groups; _b_, the fibres viewed longitudinally, one showing the creases produced by repeated bending; _c_, ends; _a′_, sections of fibres situated near the butt of the plant; mag. 300. [Illustration: FIG. 6.] Microscopic features.—Fibres transparent, regular, with tapered ends, side walls thick, consequently central canal small, smooth externally, sometimes slightly striated. Filaments easily split up into fibres. Sections.—Polygonal, regular, angles more or less acute, lumen represented by point; slight indications of concentric arrangement of fibre substance. Micro-chemical reaction.—Blue with iodine solution. General chemical characteristic.—Pecto-cellulose. Composition of raw fibre.—This varies with the different species, and is doubtless also influenced by variations in the {49} processes of retting. The following are the analyses of two samples of Belgian flax (heckled):— Müller. Cellulose 81·99 70·55 Fat and wax 2·37 2·34 Aqueous extract 3·62 5·94 Pectous substances 2·72 9·29 Water 8·60 10·56 Ash ·70 1·32 The chemistry of the flax fibre has been investigated by Kolb. Forms in which employed.—Scutching refuse, spinning waste, threads, rags, new and old. HEMP.—_Cannabis sativa._ Order, _Cannabinacæ_. Bast fibres: length, 22 mm.; diameter, 0·022 mm.; ratio, 1000. Illustrated in Fig. 7: _a_, _a′_, sections of groups of fibres of the first and second zone respectively; _b_, fibres seen longitudinally; _c_, ends; mag. 300. [Illustration: FIG. 7.] Microscopic features.—Compact bundles. Fibres show striæ and fissures, and often fibrillæ, detached or adherent. The central canal almost obliterated, ends of fibres large and flattened. The bundles show fine transverse markings. {50} Section.—Well marked concentric zones of fibre substance, irregular in outline. Micro-chemical reaction.—Blue and yellow reaction with iodine solution, the joint result showing green colouration. General chemical characteristic.—Pecto-cellulose. COMPOSITION OF RAW FIBRE (ITALIAN HEMP). Müller. Cellulose 77·13 Fat and wax ·55 Aqueous extract 3·45 Pectous substances 9·25 Water 8·80 Ash 0·82