EABIATM 107 



T^ 



distilled from tlie fresh 



plaut, grown at Mitcham, by Moss had a decided yellow colour, 

 and a sp, gr. of '9107 at G'2>^ F, With the barometer at 30 iu, 

 i-t boiled at 402^ R 



The sp, gr. of the oil after deteruiiiiing the boiliug point, 

 was fouud to be * 9117 at 62^R 



Other speciuieus of oil distilled in England from- the dry im- 

 ported herb, were found by Moss to be different- in appearance 

 and physical properties from that distilled by^ him. One 

 labelled ** non-rect." was distinctly greenj and had a sp. gr, of 

 •9 1 67 at 62^F, ; a second, labelled *^ rect.," wat^pale in colour, with 



a faint green tinge, and had a sp- gr. of 9098. The sp. gr. of 

 those oils confirni^ Todd^s gene ralization- that pure oila fall 

 between •908 and •917. {Pharm. Jonrn., p. 446, 1886.) None of 

 the three oils^ gave any coloration^ when- subjected to the test 

 given in Todd's paper above mentioned. It consists in adding 

 ^ne drop of oil to a mixture of 25 drops of alcohol with one drop 



j^ ^f nitric acid, sp. gr. I'2- With the oil of ili". piperita a 

 permanent blue or bluish-green colour is- developed. 



^ 



Chemical composition, — ;Oil of peppermint owes its peculiar 

 ©dour to menthol (mint camphor, mint stearopten), C^^H^'^0, 

 which is ehieS^y contained in th-e last portions obtained on sub- 

 jecting the oil to fractional distillation. It forms colourless 

 prisms which fuse at 42*^ C. and boil at 212^0. Distilled 

 jfli with phosphoric anhydride, it yields menthene G^^H^^, which 

 ^ is a colourless liquid of an agreeable odour. According to 

 ^ Moriga {1881), oil of peppernnnt contains probably also an 

 oil of the formula C^°H*^0, which may be prepared from 

 menthol by oxidation with potassium bichromate; but by 

 ^^ treatment with fuming nitric acid menthol yields at first an 

 explosive oil, afterward crystals of an acid (C'H^O^)^H^O 

 ^* melting at 97^C, ; this compound is not identical with pyro- 

 ]jiJ tartaric acid, with which it agrees in composition. A compound 

 ^1^ isomeric with borneol had been found by Beckett and Wright 

 (1875) in the liquid portion of Japanese peppermint oil, but, 

 4 according to Fiuckiger and Power (1880), is not present in 



