HERBA MENTHiE PIPERITA. 481 



Chemical Composition — Spearmint yields an essential oil (Oleum 

 Menthce viridis) in which reside the medicinal virtues of the plant. 

 Kane,^ who examined it, gives its sp. gr. as 0914, and its boiling point 

 as 160° C. The oil yielded him a consideraLle amount of stearoptene. 

 Gladstone- found spearmint oil to contain a hydrocarbon almost 

 identical with oil of turpentine in odour and other j)hysical properties, 

 mixed with an oxidized oil to which is due the peculiar smell of the 

 plant. The latter oil boils at 225° C. ; its sp. gr. is 0-951, and it was 

 ibund to be isomeric with carvol, C'"H"0. According to our experi- 

 ments the oil, distilled from Curled Mint grown in Germany, deviates 

 the plane of polarization 37°'4 to the left when examined in a column of 

 100 millimetres. We prepared from it the crystallized compound 

 (C'''H"0)^SH-^, and isolated from it the liquid C^^'H^O, which differs from 

 carvol (see Fructus Carui, page 30G) by its levogyrate power.^ 



Uses — Spearmint is used in the form of essential oil and distilled 

 water, precisely in the same manner as peppermint. In the United 

 States the oil is also employed by confectioners and the manufacturers 

 of perfumed soap. 



Substitutes — Oil of spearmint is now rarely distilled in England, 

 its high cosf* causing it to be nearly unsaleable. The cheaper foreign 

 oil is offered in price-currents as of two kinds, namely American and 

 German. Of the first we have already spoken : the second, termed in 

 German Krauseminzol, is the produce of Mentha aquatica h.xur. ycris2M 

 Bentham, a plant cultivated in Northern Germany. Its oil seems to 

 agree with the oil of spearmint. 



HERBA MENTHiE PIPERITA. 

 Peppe'rmint ; F. Menthe poivree ; G. Pfeffemiinze. 



Botanical Origin — Mentha 'piperita Hudson (non Linn.), an erect 

 usually glabrous perennial, much resembling the Common Spearmint of 

 . the gardens, but differing from it in having the leaves all stalked, the 

 flowers larger, the upper whorls of flowers somewhat crowded together, 

 and the lower separate. In the opinion of Bentham it is possibly a mere 

 variety of M. hirsuta L., with which it can be connected by numerous 

 intermediate forms. 



Peppemiint rapidly propagates itself by runners, and is now found 

 in wet places in several parts of England, as well as on the Continent. 

 It is cultivated on the large scale in England, France, German}^, and 

 North America. 



History — Mentha piperita was first observed in Hertfordshire by 

 Dr. Eales, and communicated to Ray, who in the second edition of his 

 Synopsis Stirpium BHtannicai'um, 1696, noticed it under the name of 

 Mentha spicis brevioribus et habitioribus, foliis Menthce fuscoi, sapore 

 fervido piperis; and in his Historia Plantarum^ as " Mentha palustna 



'^ Philosophical Magazine, xiii. (1838)444. ^ Price from 1824 to 1839, 40s. to 48x. 



^ Journ of Chemical Society, ii. (1854) per lb. 



11. 5 Tomus iii. (1704) 284. 

 ^Fluckiger, Pharm.Joiirn. vii. (1876)75. 



2h 



