Encyclopedia Britannica (11th ed.) article on hemp, Cannabis sativa, covering the botany of the plant, its cultivation and retting (compared with flax), and the other plants whose fibers are loosely called hemp. It discusses uses of the fiber for rope, sailcloth, sacking and coarse cloth, with ancient and medieval history of hemp textiles. It also covers hemp resin drugs (bhang, ganja, charas), seed and oil products, and the pharmacology of cannabis.