CRUDE DRUGS. 567 



Volatile oil of caraway contains 50 to 60 per cent, of d-car- 

 vone (carvol), and 40 to 50 per cent, d-limonene (carven). Car- 

 away oil, particularly carvone, is colored yellow on exposure to 

 air, and the old oil gives a reddish-violet color with ferric chloride 

 solution. 



Allied Drugs. The seeds of Nigella sativa and N. damas- 

 cena (Fam. Ranunculaceae), are used in medicine and for flavor- 

 ing like caraway. They are commonly known as Black Cara- 

 way. The seeds are ovate, 3- to 4-angled, about 3 mm. long, 

 externally black and reticulate; internally, a large, white, oily 

 reserve layer in which is embedded the small, greenish embryo. 

 Black caraway contains 1.5 per cent, of a volatile oil; 1.5 per 

 cent, of a glucoside. melanthin, which resembles saponin and 

 helleborin ; a fluorescent alkaloid, damascenin, giving the volatile 

 oil from N. dmnascena its fluorescence ; another alkaloid, conni- 

 gelline ; and about 35 per cent, of a fixed oil. 



CONIUM. POISON HEMLOCK. The fruit of Conium 

 maculatum (Fam. Umbelliferae), a large biennial herb in- 

 digenous to Europe, and naturalized in North and South Amer- 

 ica and in various parts of Asia (p. 352). The fruit is collected 

 when full grown but still green from wild plants, carefully dried 

 and preserved. 



Description. Mericarps usually separated ; cremocarp 

 broadly ovoid, slightly compressed laterally, 3 to 4 mm. long, 

 about 2 mm. in diameter, with a pedicel 3 to 5 mm. long, exter- 

 nally grayish-green, with 10 straight more or less crenate yellow- 

 ish ribs, stylopodium depressed, internally greenish-brown, with 

 a slender carpophore attached to each mericarp, the latter 

 5-angled in cross-section and without any vittse ; seeds reniform, 

 with a deep furrow on the commissural side, and with a small 

 embryo at the upper end of the reserve layer; odor distinct; taste 

 slight. 



Inner Structure. See Fig. 248. 



Constituents. The most important constituent is the liquid 

 alkaloid coniine (hexa-hydropropyl pyridine), which exists to 

 the extent of 0.5 to 3 per cent. ; the drug also contains conydrine 

 (oxyconiine), which crystallizes in plates, is dextrorotatory and 

 very poisonous; pseudoconydrine (an isomer of conydrine), 



