FERMENT OILS. 369 



thought, but to the decomposition of the oil contained in the pips 

 of the f^rape under the influence of fermentation, and that the 

 veritable " bouquet " may be obtained by fermenting pure sugar 

 with washed yeast, to which has been added an emulsion prepared 

 with the pips of the grape. This theory is rather remote. 



All the aliove-mentioned products are totally distinct from the 

 compound intended to be known as " Heavy oil of wine" by 

 pharmacists ; an exact scientific definition of which yet appears to 

 be wanting. The subject is of sufficient importance to have 

 attracted the attention of Professor Frederick B. Power, a very 

 eminent authority on organic chemistry, especially the chemistry 

 of ethereal oils. He has most exhaustively reviewed the facts 

 published concerning this compound, in a paper in the " Pharma- 

 ceutische Eundschau," November, 1891, and yet asks " What is 

 heavy oil of wine ? " (referring to the Oleum cethereitm of the 

 Pharmacopoeia). The inference is — that a standard of the identity 

 and purity of this official compound is not established. On 

 refering to " Gmelin's Handbook of Chemistry," xiii., p. 177, we 

 find that licavy oil of vjine or the so-called sulphovinate of luine oil 

 as distinguished from the light oil of wine, was discovered by 

 Hennel in 1826, and that it is obtamed in the following manner : — 

 " It passes over in the preparation of ether, towards the end of 

 the distillation. It is formed, but in exceedingly small quantities, 

 not only on distilHng, but immediately on mixing alcohol with 

 sulphuric acid (Marchand). It is also produced when ether is 

 acted upon by anhydrous sulphuric acid (Liebig), and by the dry 

 distillation of the sulphovinates." With regard to tlie method 

 for its preparation, the following is further recorded: — 1^ — When 

 1 part of alcohol is distilled with 2h parts of sulphuric acid, a 

 little ether passes over first, then a yellowish oil and an aqueous 

 ethereal liquid ; the former is separated from the latter, and 

 freed from uncombined sulphuric acid and a part of the 

 sulphurous acid, the alcohol and the ether, by agitation with water 

 (which, according to Liebig, should be ice-cold). The oil is then 

 separated from the water, and placed over sulphuric acid, under 

 the receiver of an air-pump, which is slowly exhausted in order 

 that the evaporation of the ether and sulphurous acid may not 

 cause the liquid to boil violently (Serullas). 2^ — Crystallised 

 sulphovinate of lime is dried carefully and completely in vacuo, 



AA 



