192 



greater than in either of these. Nature, however, may aid it in the 

 fact that the prodnction of sugar is a function incident to the plant, 

 while with beets and sorghum this is an educated quality. Time only 

 can tell which of these three will ultimately excel in the world's sugar 

 production, but whatever the outcome will be it is certain cane can take 

 a great stride in the race, now that it has been found that seed selection 

 will aid it." 



CONTRIBUTION TO THE STUDY OF THE PRO- 

 DUCTION OF THE AROMA IN RUM. 



By Percival H. Greg. 

 II. 



The Fruity Acid. 



In the March issue of the Bulletin under the head of " Eum Analysis," 

 I mentioned the existence of a fruity acid in Rum, and promised some in- 

 formation as to its occurrence in nature. The existence of fruity acids in 

 Rum is mentioned by Herzf eld ; whether this fruity acid which I have un- 

 der notice is the same, it is impossible to say with certainty, but probably 

 it is. The smell of this acid or acids, (for I have not yet attempted to pre- 

 pare it in a state of absolute purity) is extremely agreeable, and confers 

 on rum, when dissolved in it, a fruity smell more resembling that of 

 raisins than anything else I can think of. It is however in the state 

 of fruit ether, i.e., when chemically combined with alcohol, that it ex- 

 ercises the greatest influence on the aroma of rum. 



The smell of the fruit-ether is very delicious, reminding one somewhat 

 of acetic ether and perhaps somewhat more remotely of the smell of the 

 essential oil of limes, but it is exceedingly difficult to characterise an 

 aroma in words and perhaps it would be safer to call it simply " fruity." 

 The aroma however differs from the ordinary fruit-ethers in not being 

 so " fiery" and is of a softer and less penetrating nature. 



I first discovered the presence of this acid in old dunder in which it 

 was present in large quantity. This dunder when put up in the vats at 

 the end of crop did not, as far as I could ascertain by smell, contain any 

 of this fruity acid. As time went on an acetic fermentation took place, 

 and large masses of " mother of vinegar" were discovered in the liquid. 

 After a time the smell of vinegar became less distinct, owing no doubt 

 to the partial evaporation of the acetic acid and partly no doubt to the 

 further combustion of the acetic acid into carbonic acid and water, and 

 the fruity smell became very distinct. An extraction of the dunder by 

 means of petroleum ether was undertaken, and a fruity smelling residue 

 was left behind on the evaporation of the solvent. A minute drop of 

 caustic soda was added and the smell instantly disappeared, but reap- 

 peared on the addition of a slight excess of sulphuric acid. It is evident 

 therefore th*t this substance is of an acid nature The question now 

 was, how did this acid come into the dunder ? It was not there when 

 the dunder was put up in its fresh state, but it was found and was evi- 

 dently present in considerable quantity oa the conclusion of an acetic 

 fermentation. The first idea which occurred to me was, that it was 

 formed by some kind of bacterium peculiar to Jamaica, but to have 

 proved this would have necessitated a laborious series of pure cultiva- 

 tions, which, in the case of bacteria, is attended with considerable dif- 

 ficulty. The other possibility was that the fruity acid was originally 



