River, doubtfully extends into the range country. It has sumac- 

 like (pinnate) leaves, a lacquer-producing sap, and is notorious as 

 a skin-irritant. 



One or more of these poisonous species occur in every section of 

 the United States, western poison-ivy and Pacific poison-oak being 

 the far western representatives. Persons unfamiliar with these 

 plants may lessen the danger of contracting "ivy" poisoning by ob- 

 serving the following simple precautions: (1) Avoid shrubs or vines 

 with clusters of white, cream-colored or ivory, berrylike fruits; (2) 

 avoid low, erect and climbing shrubs with the leaves divided into 

 three leaflets, better expressed by the homely saying, "Leaflets three, 

 let it be"; and (3) in the eastern United States, also avoid wet- 

 site shrubs or small trees with smooth, pale bark whose leaves are 

 alternate, divided into more than seven leaflets, and have untoothed 

 margins. 



Hill, Mattacotti, and, Graham, 8 of the Hall Laboratory of 

 Chemistry, Wesleyan University, isolated and identified urushiol 

 (C2iH 32 O 2 ) as the toxic principle of Rhus toxicodendron. Urushiol 

 is a yellow, slightly volatile oil, first obtained by a Japanese scientist, 

 R. Majima, from the Japanese lacquer-tree (T. vernivifluum, syns. 

 R. vernicifera, R. verniciflua) , a first cousin to our eastern poison- 

 sumac, and the source of the famous black varnish, or lacquer of 

 the Orient. The three American experimenters mentioned above 

 verified the findings of J. Toyama, another Japanese scientist, that 

 the hydroxyl groups in urushiol are the chief cause of its well-known 

 violently vesicant action. Grant and Hansen 3 state: "All parts of 

 the plant contain the poison, even after long drying, but growth 

 in which the sap is abundant is the most dangerous." Poisoning 

 usually results from touching or brushing against the plants or 

 from handling clothing or other objects which have been in contact 

 with them. Many persons maintain that they have been poisoned 

 merely by being in the vicinity of the plants without actually touch- 

 ing them, although scientific research thus far has not substantiated 

 this contention. Unquestionably, however, numerous severe cases of 

 poisoning have resulted from smoke from the burning plant. Al- 

 though many persons are practically immune, it is doubtful if any- 

 one is wholly free from susceptibility to the poison, as apparent 

 immunity may disappear at any time. 3 If taken internally in suf- 

 ficient amount, the poison acts as a violent irritant ; cases have been 

 reported of poisoning among children from eating the fruits. The 

 lower animals are not poisoned, apparently, and livestock and game 

 animals consume the leaves, at least, without harmful effects. 



Cures for poison-ivy poisoning are legion ; practically as numerous 

 as the cases of poisoning. This results from the fact that the der- 

 matitis, or skin rash, is naturally self -limiting, and the eventual cure 

 spontaneous, so that whatever remedy is used is likely to be heralded 

 as a sure cure for "ivy" poisoning. Mild cases usually subside in a 

 few days. However, several fatalities are on record as a result of 

 extensive and severe inflammation ; in serious cases it is wise to con- 



3 Sre footnote on preceding page. 



8 Hill, G. A., Mattacotti, V., and Graham, W. D. THE TOXIC PRINCIPLE OP THE POISON 

 IVY. Jour. Amer. Chem. Soc. 56 (12) : 2736-2738. 1934. 



