R. rad'icans, Rhus Toxicodendron, Poison Ivy. -- The fresh leaflets, U.S.P. 1870-1890; N. America. Climbing plant over fences, rocks, trees, etc.; flowers small; fruit smooth drupe. Leaflets, collected May-June, trifoliate, petiolate, entire, glabrous, the 2 lateral nearly sessile, 10 Cm. (4') long, obliquely ovate and pointed; when dry brittle, inodorous, astringent, when fresh with acrid juice blackening on exposure, applied to skin produces swelling, inflammation, etc. -- hence should not handle ungloved or confound with the harmless Pte'lea trifolia'ta, Three-leaved Hoptree, whose leaflets are sessile, thicker, paler green; contains toxicondendrol 3.3 p.c., tannin, acetic acid (formerly considered toxicodendric acid); toxicodendrol, the active, irritating, poisonous principle, is a viscid, non-volatile oil (or freed fat acid, or complex glucoside), agreeably odorous, soluble in alcohol, benzene, ether, chloroform, decomposed by heat. Irritant, rubefacient, narcotic, poisonous; internally produces gastro-intestinal inflammation, vertigo, nausea, muscular debility, delirium, mydriasis, convulsions, death. Poisoning: The fresh leaves, juice or flying pollen produce external itching, burning, redness, tumefaction, vesication, desquamation, lasting 1-2 weeks. Apply at once soap and water with scrubbing-brush, lead water and laudanum, alkaline solutions (sodium bicarbonate--8 p.c. solution 3-4 times daily, sulphite, chlorinated, thiosulphate, diluted ammonia, soapsuds, alum curd), or hot aqueous saturated solution of magnesium sulphate (frequently), or fresh bruised leaves of either fire weed (Erectites hieracifolia), touch-me-not (Impatiens aurea, biflora) or burdock (Arctium Lappa), or solution of sodium salicylate (2), + fldext. hydrastis (1) + water (5), or tincture or infusion of lobelia, grindelia, or sassafras, cocaine solution 4-8 p.c. (to relieve burning and itching), aristol, glycerite of phenol, opium -- no oils, vaselin, alcohol, these being solvents of poison serve to disseminate it, low diet, saline purgatives, quietness. Used in chronic eczema, skin diseases, erysipelas, rheumatism, incontinence of urine, etc. Dose, gr. 2-5-15 (.13-.3-1 Gm.); tincture (fresh leaves bruised and macerated with equal weight of alcohol, m 1/10-1 (.006-.06 cc.); juice (expressed from leaves and preserved with alcohol) is soluble in ether and possesses all the virtues of the plant; fluidextract, mv-30 (.3-2 cc.). R. Toxicoden'dron, properly more or less shrubby, .6-1 M. (2-3 degrees) high, erect, leaflets crenately lobed, pubescent, called also Poison Ivy (Oak)--merely a variety of R. radicans. R. diversi'loba, Pacific coast; leaves with 3-5-lobed, pinnatifid leaflets. R. Ver'nix (venena'ta), Canada, United States, swamps, 3-6 M. (10-20 degrees) high; leaves of 7-13 entire leaflets; fruit yellow; called poison-sumac(h), -dogwood, elder, and yields most toxicondentrol. R. pu'mila, S. Carolina, procumbent shrub; leaves pinnate with 11-toothed acuminate leaflets; fruit red, hairy. All of these are poisonous, but R. Vernix the most so, as when in flower it so taints the surrounding air that sensitive persons become poisoned by simple exposure to the effluvium.