Curari, URARI, WOORALI, or WOORARA, is a celebrated poison used by some tribes of South American Indians for poisoning their arrows. It is by means of this poison that the small arrows shot from the Blowpipe (q.v.) become so deadly. It is brought to Europe as a black, brittle extract, resinous in appearance, and encrusting the sides of little gourds containing it. The source of this deadly poison was for long unknown, owing to the natives jealously guarding the secret. The process of manufacture has now, however, been witnessed and described by several travellers, and in each case some species or other of Strychnos has been recognised as the source of the poison. There seem to be four distinct varieties of curari, each characteristic of a different tract of country, and probably varying in their physiological action; but for our purpose we may confine ourselves to that kind which is used in physiological experiments. Curari is one of those poisons which have little action when taken into the stomach, owing to the difficulty with which they are absorbed, but when introduced into a wound it acts with great promptness. The symptoms caused are loss of muscular power, feeble respiration, and death by suffocation. By means of artificial respiration it is possible to sustain life for a lengthened period, although the animal is apparently insensible to pain. In this way it is employed in vivisection experiments as an anaesthetic.
At first it was supposed that curari contained strychnine, but as its action was so entirely different, this view was soon abandoned. Prolonged research has separated a special alkaloid, Curarine, which possesses the leading properties of the poison itself. Curarine differs from all other crystallisable alkaloids, save one, in containing no oxygen. It forms salts, and is said to be twenty times as strong as curari. In medicine curari is very little used. It has been proposed to employ it in lockjaw, hydrophobia, and as an antidote in poisoning by strychnia; but although it quiets the spasm, it has no direct curative effect, and it may cause an equally fatal paralysis.
Besides curari proper, there are two other arrow-poisons called Corroval and Vao. These, which are brought from New Granada, have an entirely different action on the body, as they primarily stop the beating of the heart, whereas with curari the heart continues to beat after breathing has ceased.