Upas Tree, a Javan tree belonging to the breadfruit family (artocarpeoe), which botanists now unite with the mulberry family (moreai). The native name of the tree is bohun upas, and its resinous and highly poisonous exudation is called antiar, a name used for the genus, antiaris; while this species (A. toxicaria) is poisonous, others are innocuous. The tree reaches 100 ft. or more in height, with a straight trunk and a handsome rounded head; the oblong or ovate leaves, 3 to 5 in. long, are much veined and downy; the monoecious flowers are small and inconspicuous, the pistillate being succeeded by an oval, purple drupe, in appearance like a small elongated plum. When the tree was first made known extraordinary stories were told about it on the authority of Foersch, a surgeon in the service of the Dutch East India company near the close of the 18th century; he represented that the emanations of the upas tree killed all animals that approached it, even birds that flew too near it falling dead; that criminals condemned to death were allowed as an alternative to go to that tree and collect some of the poison, only two out of 20 ever returning; and that he had learned from those fortunate enough to return that the tree was in a valley, with no other tree or plant within 10 or 12 m. of it, all being a barren waste, strewn with human and other bones; he also said that out of a population of 1,600, who were forced by a civil war to take refuge within 12 or 14 m. of the tree, only 300 were alive at the end of three months.
These stories were accepted until they were disproved by Leschenault, whose memoir (Annales du museum (d'stoire naturelle, 1810) is translated in Hooker's "Companion to the Botanical Magazine," vol. i. So far from growing in a solitary desert, the upas is found in the forests with other trees, and lizards and other animals do not avoid it; its poisonous emanations appear to have a similar effect to those of our poison ivy and sumach, and to affect some persons and not others; several botanists have since collected specimens without unpleasant results, and living plants of upas are now in the principal botanic gardens of Europe, where they are not known to be harmful. It is supposed that the story of the valley of death had its origin in the fact that there was some locality in a volcanic country where an abundant emission of carbonic acid gas produced the fatal results ascribed to the upas tree. • The poison has long been used by the natives upon their arrows and other implements of war and the chase; the basis of the poison is the juice of the tree, collected by making incisions, and with this they mix, as do the South Americans in preparing woorara, various other substances, which seem to be more required by tradition than for any efficacy they can add to the poison; among those mixed with the upas are the juice of the onion and garlic, cardamom, black pepper, and seeds of a capsicum.
When introduced into the circulation of an animal, it acts upon the vascular system, and causes a congestion of the principal viscera, especially the lungs, and death follows in a few minutes. The natives of the same countries use another and more deadly poison, tieute, from a species of strychnos, which at once affects the nervous system and causes almost instant death. The inner bark of the upas tree affords a fibre which is spun into cloth and worn by the poorer classes as a substitute for linen; if this accidentally gets wet, it produces an intolerable itching. Another species, A. sacczdora, of Malabar, has a bark so tough that bags for rice and other articles are made from it; the branches are cut into truncheons of the proper size, and the bark removed in such a manner as to leave a thin section of wood as a bottom to the bag.
Upas Tree (Antiaris toxicaria).