Scientific and other notes on essential oils. 35 



its content of free or esterified menthol is performed in the following manner: 50 ccm. 

 peppermint spirit are filled into a measuring flask holding 50 ccm. and weighed; hereupon 

 the spirit is transferred into a small cassia-flask, , rinsing the flask three times with 

 10 ccm. of water, water added up to the mark, and the vessel allowed to stand at 

 least 4 hours. The quantity of oil which has separated is read off and the oil yield 

 of the spirit calculated, expressed in per cent, by volume. 



One or 2 ccm. of the oil are then poured into a previously weighed cylinder which 

 besides is divided into tenths of a ccm. and the content of peppermint oil in the 

 spirit calculated from the weight obtained, expressed in per cent, by weight. The oil 

 remaining in the neck of the small cassia-flask is then carefully removed and the 

 aqueous liquid employed for ascertaining its alcohol content. 



The oil remaining in the tared cylinder is transferred into an Erlenmeyer-flask, 

 weighed and saponified, in order to determine is menthyl acetate content. 



The saponified oil is now acetylated and saponified to ascertain its menthol 

 content. In order to determine the alcohol content of the spirit of peppermint the 

 watery-alcoholic liquid from the small cassia-flask is poured into a fractionating flask 

 and the cassia-flask rinsed with 100 ccm. of water. Finally, after distilling not quite 

 100 ccm. of this liquid into a measuring flask of 100 ccm., one fills up to 100 ccm., 

 determines the specific gravity of the liquid, and calculates therefrom its alcohol-content. 



Peppermint Oil, American. The influence of climatic conditions or the quality 

 of the soil are frequently adduced as reasons for diversity in the quality or com- 

 position of volatile oils. Experiments with this object in view have only rarely been 

 made, and it is very doubtful if the variations which have been observed can always 

 be explained by the causes mentioned above. A publication by F. Rabak 1 ), which has 

 been issued by The Bureau of Plant Industry of the U. S. under the designation 

 of "The Influence of cultivation and Climatic conditions on the Yield and Quality of 

 Peppermint oil", is well worth our attention. He cultivated peppermint plants under 

 various climatic conditions on soils differing widely and distilled the material obtained 

 from plants in various stages of development, besides trying to arrive at definite con- 

 clusions by not only distilling the entire plants, but also in parts, in a dry as well as 

 in fresh state. The plants were cultivated at Webster, South Dakota, on a dark, 

 fertile, loamy soil, at Glenn Dale, Md., on a light, sandy soil, and at Arlington Farm, 

 Va., on a heavy, clay soil. The results obtained proved that the quality of the soil 

 had very little effect indeed on the yield, the same applied to the colour, smell, and 

 taste of the oils, whereas the optical rotation and refraction showed very great 

 differences. The oil from Arlington (fertile, loamy soil) was specifically lighter and 

 rather more soluble in 80 per cent, alcohol than the others. The Arlington oil con- 

 tained less esters and a smaller amount of total menthol than that from Webster, 

 whereas the oil from Glenn Dale was the richest in esters. 



This and the investigations of other authors 2 ) leads Rabak to the conclusion that 

 light, sandy or loamy soils are more favourable for the production of esters and 

 menthol in peppermint oil than soils of a heavy nature. Climate seems to have very 

 little effect on the production of the oil. Table I gives the results concerning qualities 

 and yields in oil from plants in various soils. 



x ) U. S. Dep. Agric. Bull. N° 454, Washington 1916. — •) H. J. Henderson, Pharmaceutical Journ. S7 (1911), 

 175; Report October 1911, 70. — }. C. Umney, Pharmaceutical Journ. 57 (1896), 103; Report October 1896, 

 59. — E. Charabot and A. Hebert, Compt. rend. 136 (1903), 160. — G. Mossier, Uber Jen Einjfuss cerschicdener 

 Kulturbedingungen auf das dtherische Ol von Mentha piperita, Pharm. Post 45 (1912), 2. 



3* 



