CRUDE DRUGS. 631 



Oil of Russian pennyroyal contains pulegone, but the botanical 

 origin is not known. 



MENTHA PIPERITA. PEPPERMINT. The leaves and 

 flowering tops of Mentha piperita (Earn. Labiatae), a perennial 

 herb (Eig. 175) indigenous to Europe, naturalized in the Eastern 

 and Central United States and Canada, and cultivated in Michigan 

 and New York (p. 370). Peppermint should be collected during 

 dry weather, in August and September, when the plant is in 

 flower, and carefully dried and preserved. Peppermint is culti- 

 vated in Michigan chiefly for its volatile oil. This State produces 

 annually over 6,800 K. of peppermint oil. Wayne County, in 

 New York State, produces 1,480 K. ; Indiana State, 1,280 K., and 

 other localities about 400 K. annually. Japan produces about 

 70,000 K. annually ; England, 9,000 K. ; France, 3,000 K. ; Russia, 

 1200 K. ; Germany, 800 K., and Italy, 600 K. 



Description. Stem quadrangvdar, i to 3 mm. in diameter, 

 purplish-green, with scattered deflexed hairs, internodes 1.5 to 5 

 cm. long. Leaves ovate-lanceolate, opposite, 1.5 to 8 cm. long, 

 0.5 to 2.5 cm. broad ; apex acute ; base acute or rounded ; margin 

 sharply serrate ; upper surface dark green, midrib and veins rose- 

 colored, the latter diverging at an angle of about 60, curving 

 upward and uniting near the margin ; under surface light green, 

 slightly pubescent on the veins, glandular-pubescent ; petiole 4 to 

 10 mm. long, slightly pubescent. Inflorescence in axillary whorls 

 or in compact spikes ; peduncle wanting or about 3 mm. long, 

 pedicel about i mm. long; calyx tubular, equally 5-toothed, about 

 2 mm. long, purplish, glandular-punctate ; corolla tubular, nearly 

 regular, 4-cleft, about 3 mm. long, purplish ; stamens four, erect, 

 distant. Nutlets ellipsoidal, about 0.5 nini. in diameter, blackish- 

 brown. Odor aromatic. Taste aromatic, followed by a cooling 

 sensation. 



Constituents. Volatile oil, containing 50 to 60 per cent, of 

 menthol, about i per cent. ; resin and tannin. American pepper- 

 mint oil consists of about 17 different chemical constituents, a 

 larger number than is found in any other oil. The most impor- 

 tant constituent is the stearoptene menthol, of which 40 to 45 per 

 cent, is free and 8 to 14 per cent, is combined in various esters. 

 Menthol occurs in colorless, acicular crystals, which are insoluble 



