— 77 — 



In referring to the differences between Grasse peppermint oil and 

 that of other origin, Roure-Bertrand Fils also call attention to the 

 fact that the Grasse variety would not be admitted by most Phar- 

 macopoeias. If the fiim should conclude from this that the require- 

 ments of the Pharmacopoeias have been laid down "without sufficient 

 technical knowledge", such a judgment must be regarded as some- 

 what too severe. Outside France, French oil does not enter into 

 commerce at all, and it is therefore not surprising if the Pharmacopoeias 

 have not paid special attention to it. 



As a special peculiarity of the Grasse oil, Roure-Bertrand Fils 

 mention its behaviour in a freezing mixture. Even when cooled down 

 to — 1 7 it was impossible to bring the oil to congealing point, even 

 after inoculating it with menthol. It is hoped that the intended examin- 

 ation of the alcoholic constituents will explain this behaviour of the oil. 



To the foregoing we would add that in the case of the highly 

 esteemed English and Saxon oils also crystalline separations frequently 

 only take place after the oils have remained for a long time in the 

 freezing mixture; hence the quantity of crystallisable menthol differs 

 altogether in the oils of various origin, and is not a direct measure 

 of their value. At the same time we refer to our own communications 

 on South French peppermint oils *), which partly behaved similarly to 

 to those examined by Roure-Bertrand Fils. We may further 

 place on record here an observation which we have made concerning 

 the rapid resinification of two oils distilled by ourselves in Barreme. 

 Both oils were examined some weeks after distillation, and at first 

 behaved as follows: — 



i • di5° 0,9184 ; aj) — io°44 ; mthl. as ester 1 2,0 °/ ; total mthl. 50,2 °/ I 8op.c. ale.; with 



> more than 2, 5 to 



2. di5° 0,9273; ctD — I0°56'; „ „ „ 14,8%; „ 54,70/ 3vol. pronounc. 



I opalescence. 



Accidentally the specific gravity was again determined a fortnight 

 afterwards, on which occasion a considerable increase in weight was 

 ascertained. Two following observations, made at intervals of a fortnight 

 each, showed a further increase, which is indicated in the following 



table: — 













Originally 



After a fortnight 



After 4 weeks 



After 6 weeks 



Oil 1. 



di 5 o 0,9184 



0,9191 



0,9224 



0,9292 



„ 2. 



d i5 o 0,9273 



0,9291 



0,9322 



0,9380 



The reason for this is to be found in the fact that the herb had 

 been worked up while it was still quite green. In such a state, 

 readily resinifying constituents pass into the oil, which, if the herb 



*) Report April 1905, 62; October 1906, 58. The places of origin of the 

 oils were Cannes, Cagnes, Castellane, and Barreme. 



