632 BOTANY AND PHARMACOGNOSY. 



in water but soluble in alcohol, and on boiling with a sulphuric 

 acid solution (50 per cent.) it becomes of a deep blue color, the 

 acid solution becoming brown. American peppermint oil also con- 

 tains : Acetaldehyde, isovaleraldehyde, acetic acid, valerianic acid, 

 pinene, phellandrene, cineol, 1-limonene, menthone, menthyl 

 acetate, menthyl iso-valerianate, menthyl ester, a lactone cadinene, 

 amyl alcohol, and dimethyl sulphide. 



English peppermint oil is very highly prized on account of 

 its fine aroma and pleasant taste. It consists of 50 to 60 per cent, 

 of free menthol, 3 to 14 per cent, of menthol combined as esters, 

 and 9 to 12 per cent, of menthone, a substance capable of being 

 transformed into menthol. This oil also contains : Phellandrene, 

 limonene, cadinene, acetic acid and iso-valerianic acid. 



Japanese peppermint oil is obtained from Mentha arvensis 

 piperascens. The oil has a bitter taste and consists of free men- 

 thol 65 to 85 per cent. ; menthol combined as esters, 3 to 6 per 

 cent. ; and a body isomeric with borneol. 



MENTHA VIRIDIS.— SPEARMINT.— The leaves and 

 flowering tops of Mentha spicata (Syn. Mentha viridis) (Fam. 

 Labiatse), a perennial herb indigenous to Europe and cultivated 

 and naturalized in various parts of North America. It should 

 be collected in the same manner as peppermint (p. 370; Fig. 67). 



Spearmint is extensively cultivated in Michigan and New 

 York, these states producing annually about 500 K. of volatile oil. 



Description. — Closely resembling peppermint (see Mentha 

 Piperita), but the stems are usually more purple, the leaves sessile 

 or nearly so, inflorescence either in slender, interrupted cylindrical 

 spikes or crowded lanceolate spikes ; odor and taste aromatic, 

 characteristic, the taste not being followed by a cooling sensation. 



Constituents. — Volatile oil about 0.3 per cent, in the fresh 

 leaves ; resin, and tannin. American oil of spearmint consists 

 of about 56 per cent, of carvone, a considerable amount of 1-limo- 

 nene and possibly also 1-pinene. The constituent giving the oil its 

 characteristic odor is not known. 



Allied Plants. — Russian spearmint oil is obtained from an 

 undetermined plant and consists of 1-linalool, 50 to 60 per cent..; 

 20 per cent, of cineol, 5 to 10 per cent, of 1-carvone and possibly 

 also 1-limonene. 



