Open main menu

Page:Popular Science Monthly Volume 38.djvu/625

This page has been proofread, but needs to be validated.

of plantain (Musa textilis), belonging to the same.genus as the hanana.

Sisal hemp, the subject of this paper, is obtained from the leaves of some of the species and varieties of the genus Agave, one species of which is well known in cultivation under the name of "century plant." This genus belongs to the order Amaryllidaceæ, and is related to the snow-drop, amaryllis, and narcissus; but, owing to the much greater size of the plants, and some peculiar points of structure, it stands prominent among its congeners. The agaves are indigenous in the New World only, and the majority of the species are natives of Mexico, only a few being known within the limits of the United States.

The same general appearance is presented by all, so that any one familiar with the century plant can form a very good idea of ihe appearance of the other species of the genus. In all, the leaves are thick and fleshy, as they contain the supply of material which is to nourish the great flower-stem when the plant arrives at maturity. This stem, which is a prolongation of the trunk of the plant, shoots up from the center of the rosette of leaves, and often attains a height of from twenty to thirty feet. The time required to arrive at maturity varies in the different species, and in the same species under different conditions. The "century plant" in its native home, Mexico, blossoms in from ten to fifteen years, while with us it requires thirty, fifty, or in some cases, it is said, even a hundred years to mature. During the production of the great flower-stalk the store of nourishment in the massive leaves is exhausted, and, after the fruit is produced, the plant withers and dies.

The leaves of all the agaves contain what are known botanically as the fibro-vascular bundles. In order to see these, it is only necessary to cut off a leaf of the century plant; as, in a thick transverse section, that has been allowed to dry slightly, the fibers will look like short bristles projecting from the surrounding soft tissue; and in a longitudinal section these bristly points are seen as threads running through the leaf. Should the observer be the fortunate possessor of a compound microscope, on examining these threads he will find them composed of exceedingly fine, elongated cells, closely connected in a bundle, and surrounded by the much larger circular cells that compose the soft parts of the leaf. When the outer skin and the soft tissue of the leaf are removed, the fibro-vascular bundles remain and constitute what is commercially known as "fiber."

While all the agaves will yield fiber of some kind, it is only in a few that the quantity and quality of the material are such as to make its manufacture profitable. This fact has been known for a long time in Yucatan, the home of the sisal industry. There