“If a woven or spun fibre is to be examined it must first be disintegrated into the single fibres, and any colour or finish must be removed as completely as possible. Vertical and longitudinal microscopic sections are next made. These are rendered transparent by glycerin or chloride of calcium, and treated with tincture of iodine, made by simply dissolving iodine in a solution of iodide of potassium. The excess of this tincture is removed, a drop of dilute sulphuric acid added, and the sections examined by the aid of the microscope.
Linen Fibre.—Bundles of similar fibres, with a fine canal in the centre, long, uniformly thick, and pointed at the ends. Longitudinal section; the fibres are coloured blue, the canal yellow. Cross section: regular
polygons, loosely connected, coloured blue; centres yellow.
Hemp.—Fibres aggravated; each fibre covered with a thin skin; coloured yellow. They are thick and less uniform than the linen fibres. The ends are thick and of the shape of spatulas, and become blue or greenish blue with iodine. Cross section: irregular polygons, firmly connected; rim yellow, the mass blue, the centre colourless.
Cotton.—Longitudinal section: single fibres, spirally wound on their own axis, with a central canal and broad ends; coloured blue by iodine. The cross sections are rounded in the shape of kidneys, and coloured blue, with yellow spots interspersed.
China Grass.—Longitudinal section: fibres separated lengthwise, of varying thickness. The interior canal is often filled with a yellow granular substance, which is coloured brown by iodine. The fibre is turned blue by iodine. Cross section: irregular, with re-entrant angles, and little cohesion. The fibres are stouter than all other fibres, and are turned blue by iodine.
Jute.—Fibres strongly coherent, the ends undulating and difficult to separate. Central canal wide, empty, and gently rounded at the ends; coloured yellow. Cross section: polygons strongly coherent and regular, much like those of hemp, but the central opening is larger; coloured yellow, darker at the rim.
New Zealand Flax.—Bundles of cells of the leaves, easily separated with a needle into stiff little fibres, provided with a canal of uniform width. The sides are rolled inwards, coloured yellow. The cross section resembles that of jute, but the corners of the polygons are rounded off. They are coloured yellow by iodine tincture.
VEGETA′TION. Vegetation (which is here employed in the sense of plants in general) is very unequally distributed over the earth’s surface. Thus, towards the poles plants are found, not only in diminished numbers compared to their occurrence in warmer and more temperate regions, but also of much smaller size or stunted growth. No plants at all are met in the regions of eternal frost and snow, whilst in equatorial climes they attain to the most gigantic proportions, and are possessed of the most exquisite colours and perfumes, and yield the finest fruits. The habitat of a plant will, of course, be that on which it finds the conditions favorable to its existence and growth, in the shape of soil, climate, moisture, geographical position, &c.
VEGETATION (Metallic). This name has been fancifully applied to the following:—