Wonrali, Curari, Trail, Or Tirana Woorara Woorari, the name of several powerful poisons prepared by the natives of Para, Brazil, and the interior of British Guiana, and used by them for tipping the points of weapons employed in war and in hunting. Their real nature and origin are not completely known. One of the most widely accepted accounts of the woorara is that given by Sir R. H. Schomburgk, and asserted by him to be derived from information by the natives as well as observation; this is to the effect that the principal ingredient is the juice of a tree or shrub of the same genus with that yielding nux vomica, for which accordingly he proposes the name strycJinos toxifera. It seems probable that the different varieties come, at least in part, from several different plants, among which are the cocculus toxicophorus, strychnos Castelnceana, strychnos cogens, rouhamon Guianensis, and rouhamon curare. Like the poison of venomous serpents, woorara taken into the stomach is, at least in a large proportion of instances, entirely inert and harmless; probably because it is so difficult of absorption by the mucous membranes, that it is removed from the blood by the excretory organs as fast as ingested.

Dr. J. W. Green ("American Medical Gazette," vol. vi., p. 299) says that, taken by animals in large quantity and in an empty state of the stomach, it has caused death. The opinion that its chief ingredient is the venom of serpents is directly contradicted by the facts that the poison neither alters the character of the blood, nor excites inflammation in the wound through which it finds its way into the circulation, and also by the absence of any mention of this ingredient in some of the most trustworthy accounts. It is by no means improbable, however, that serpent venom, as well as an exudation from the skin of toads, may be introduced into some varieties. MM. Pelouze and Bernard found it to be absorbed as readily through the membrane of the air cells as when introduced into the areolar tissue. The account of Dr. Hancock, said also to be derived from information by the natives, makes the woorara a watery extract from the bark of a convolvulus or gourd-like plant. Charles Waterton, in his "Wanderings in South America" (London, 1825), enumerates as the sources of the woorara poison a vine having that name, with a very bitter root, two gourd-like plants, two species of venomous ants, pepper, and the fangs of two sorts of poisonous serpents.

From these is obtained a mixture having the appearance of a thick brown sirup, with which the arrows to be poisoned are anointed. The flesh of game killed with these arrows may be eaten at once with impunity. If the animal to be killed is large, it is sometimes necessary to use several arrows, which can be done the more easily, as the discharge of the arrows is without noise, and a hunter may successively bring down many birds or small animals with them before he proceeds to gather up his game. They are discharged by blowing from a long slender tube or blow-pipe, called gravatana. The arrows are notched, so as to break off in the wound; and by winding a cotton-like material about them they are made to fit the tube, which is of reed, and may be 8 or 12 ft. long. In Peru, arrows only 1½ to 2 in. long are used, and the poison is of a different sort. - The action of woorara has been carefully studied by physiologists, and found to consist in a paralysis of the nerves controlling voluntary motion, and later those presiding over organic life and the heart. The paralysis begins at the periphery, where the finer extremities of the nerves are distributed to the muscular fibres.

If the dose is not too large, but yet sufficient to paralyze entirely the voluntary muscles of the thorax and diaphragm, artificial respiration, kept up long enough to allow the poison to be eliminated, will prevent the death of the animal, although of course there will be no motion, with the exception of the pulsations of the heart. It is much used in physiological experiments. The sensitive nerves are affected to a less degree, or, according to the earlier views, not at all. Its uses in practical medicine are extremely limited. It has been suggested as an antidote for strychnia; but although a sufficient dose would prevent the spasm of the respiratory muscles, which is usually the cause of death in poisoning by strychnia, it would do so only by the production of an equally fatal paralysis. This, it is true, might be relieved by artificial respiration, but the experiment would be unnecessarily hazardous in the presence of better means of attaining the same object. Since the action of strychnia is exerted primarily upon the spinal cord, there is no exact antagonism between the two drugs. Similar reasoning applies to its use in tetanus and epilepsy; and as to chorea, it is too powerful to be employed in a disease not usually dangerous.

An active crystalline principle, called curarine, soluble in water, alcohol, and ether, and containing no nitrogen, has been isolated, and is active in about one twentieth of the dose of woorara. Among our ordinary drugs, the action of woorara upon the nervous system is most nearly imitated by conium (see Hemlock); but conium is readily absorbed from the stomach as well as the subcutaneous tissue.