Lactu'ca viro'sa, Lactucarium, Wild Lettuce. -- The dried milk-juice, U.S.P. 1820-1910; C. and S. Europe. Biennial herb .6-2 M. (2-6 degrees) high, glabrous, green, often purple spotted; leaves runcinate, radical and cauline, spinous apex and margin, auriculate, glaucous-green, flowers yellowish, milk-juice (lactucarium) usually in quarter sections, angular pieces, brownish, fracture tough, waxy; internally light brown, porous; odor distinctive, opium-like; taste bitter. Powder, brownish--irregular fragments without cellular structure. It is obtained by cutting off the head of each stalk and scraping the exuding juice into small vessels, repeating the process 6-7 times daily for several weeks, each cut being made a little lower down the stalk; by night, having become a viscid mass, it is divided into suitable pieces and dried by gentle artificial heat for 5 days, losing 75 p.c. in weight; solvents: water (51 p.c.), diluted alcohol (36-44 p.c.), spirit of chloroform (55-60 p.c.), being mostly lactucerin (lactucon) 50-60 p.c., lactucin, lactucic acid, lactucopicrin, caoutachoue, resin, volatile oil, ash 10 p.c. With water--turbid mixture; + iodine T.S. -- not colored blue (abs. of starch); + ferric chloride T.S. -- only faint green (abs. of tannin). There are three varieties: 1, English; 2, German; 3, French (Aubergier's). The juice of L. Sati'va, obtained like lactucarium, yields Lactucarium Gallicum, and when expressed from the stalks, clarified by coagulation, expressed and inspissated -- Thridace. Anodyne, sedative, hynotic, diuretic, expectorant, very unreliable; milder than opium, and unlike it, does not derange the digestive organs; where opium is objectionable -- to procure sleep, allay cough, dropsy, palpitation of heart, nervousness. Dose, gr. 1-8 -- 15 (.06-.5 -- 1 Gm.): Tincture, 50 p.c., dose, 3ss-1 (2-4 cc.); Syrup, 5 p.c., dose, 3j-4 (4-15 cc.; Fluidextract, dose, mj-30 (.06-2 cc.); Lozenge. L. Canaden'sis (elonga'ta), Wild Lettuce, U.S.P. 1820-1840. The herb; N. America, rich damp soil, fields, thickets; herb 1.3-3M. (4-10 degrees) high, hollow, purple leafy, glaucous; leaves 15-30 Cm. (6-12') long, pinnatifid; flowers yellow to purple, heads 20-flowered, panicles. Juice from plants in flower make good lactucarium, that collected in early season being without bitterness. L. Sati'va, Garden Lettuce, yields a juice that is medicinal and more abundant in wild than cultivated plants; highly valued as salad and as such is a feeble hypnotic. L. Sagitta'ta (altis'sima), large Caucasian plant 2.5-3 M. (8-10 degrees) high, chiefly cultivated in France.