Rohiquet on Aroma. 113 



loped, inconsequence of the decomposition of vegeto-animal 

 matter. It is a practice also to improve the snufF of inferior 

 quality, such, for instance, as comes from the refuse, by 

 adding a small quantity of the carbonate of ammonia to it. 

 The odour of the best snufF may be destroyed by mixing with 

 it a little pulverized tartaric acid ; no smell can then be distin- 

 guished but that of acetic acid arising from the decomposition 

 of the acetate of ammonia contained in the prepared snufF. 



Is it not probable, from what has been stated, that ammonia 

 contributes considerably to the existence of the odour in the two 

 cases cited, and many other facts may be mentioned in support 

 of the proceeding. M. Vogel, in describing the properties of 

 the essential oil of bitter almonds, says that, exposed to the 

 air, it concreted, crystallized, and became inodorous. He at- 

 tributes this phajnomenon to the absorption of a certain quantity 

 of oxygen, and founds his opinion on the circumstance that 

 this solid oil can resume its primitive odour on agitation with 

 a few drops of the hydro-sulphuret of ammonia ; but, according 

 to the preening observations, it appears much more probable 

 to me, that it is the ammonia, and not the sulphuretted 

 hydrogen which is the important agent. It is certain that the 

 juice of the apricot kernels taken before the almond odour is 

 developed, or immediately after its preparation, loses the 

 power of becoming odorous, if it has previously been agitated 

 a few moments with a little ether. This experiment being 

 generally made in a long tube, the ether which floats above, 

 leaves on its spontaneous evaporation traces of an oil impreg- 

 nated with a slight odour. As to the juice thus washed by 

 ether, it, as before said, no longer has the property of be- 

 coming odorous by length of time, and it has lost the power of 

 giving ammonia on the addition of the alkalies. I have already 

 said, that M. M. Vogel and Maitin had ascertained the existence 

 of an essential oil in bitter almonds, characterized by the odour 

 of prussic acid. I nevertheless regard the existence of this 

 essential oil as very doubtful ; and I think it more probable that 

 the volatile product obtained on distilling the emulsion of hitter 

 almonds, is a combination of a particular principle contained in 



Vol. X. I 



