APPENDIX 
453 
The following brief summary gives a few of the more important characteristics 
of each species of textile fiber to be studied. 
GROUP A. SEED HAIRS. 
Cotton. — Seed hairs of the cotton plant (Gossypium). Fibers are long, color¬ 
less, twisted, flattened, ribbon-like cells with thickened edges. Most fibers have 
a central air-filled canal (lumen), polarize strongly; display brilliant polarization 
colors. Consists of almost pure cellulose. No “ lignin ” present. 
Mercerized Cotton. — (Cotton treated with caustic soda.) Differs from ordinary 
cotton in being cylindrical, rarely flat and is usually free from twists. The cells 
are more lustrous, more transparent, and show fewer markings or striations. 
Kapok. — Seed hairs of Eidendron (species) and Bomhax (species). Fibers are 
thin, lustrous, transparent (under microscope in water), smooth, usually showing 
no markings or striations. Cells are almost uniform in diameter, tapering rather 
abruptly to a point at one end. The bases of these hairs, where attached, are 
swollen, bulbous, and the swollen portions are distinctly reticulated. Commercial 
samples consist largely of broken, doubled over and irregularly bent hairs. Polariz¬ 
ation very weak. 
GROUP B. BAST FIBERS. 
Linen. — Bast fibers from the stems of flax (Linum). Individual fibers are long 
pointed cylindrical cells; colorless, fairly uniform in structure. Many possess 
a central lumen usually as a narrow line which often appears to be double. Char¬ 
acteristic slight swellings or nodes are to be found at fairly regular intervals, with 
fine almost invisible cross-lines. Nodes, dislocations and cross-lines more pro¬ 
nounced in woven fabrics than in raw flax, and are distinct in worn linen. Raw 
flax contains both “ lignin ” and cellulose. Bleached linen contains substantially 
no “ lignin.” Usually polarize strongly and show brilliant polarization colors. 
Hemp. — Bast fibers from hemp plants {Cannabis). Bundles of long blunt 
cells, not pointed at the ends as in flax; many cells have forked ends. All show 
large well-defined central lumens. Long cells usually striated; cross-lines more 
prominent than in flax. Nodes absent, but dislocations frequent and well marked. 
In cross-section fibers are irregularly oval, and lumen flattened and irregular. 
Polarized feebly, no polarization colors. 
Jute. — Bast fibers from a number of species of Corchorus. Bundles of fibers 
whose cells are much shorter than hemp and with tapering, somewhat more pointed 
ends than hemp. Lumen almost central, large, well defined, and often interrupted, 
of irregular diameter, varying from one-half or more the diameter of the cell to a 
narrow black line. Cell walls with longitudinal striations but free from cross 
striations. In cross-section the cells are polygonal, five or six sided, with large oval 
lumen. Fibers which have been thoroughly freed from vascular tissue polarize 
feebly. 
Ramie — China Grass. — These two terms are applied interchangeably in com¬ 
merce to certain linen-like fabrics made from the bast fibers of a number of very 
different plants. Usually these fabrics are somewhat coarser than linen but have 
a higher luster or sheen. Strictly speaking the term Ramie should be restricted 
to the bast fibers obtained from several species of Boehmeria, while China Grass 
