1&3 



present in the dunder as a salt, and had been set free from its combi- 

 nation with a base under the influence of nascent acetic acid, which 

 would enter into combination with the base in the place of the " fruity" 

 acid, that is, that an acetic acid fermentation had played an essential part 

 in its formation. Now remembering that " dunder" is the residue of 

 cane juice, it was highly probable that if this acid was present in the 

 dunder in the manner I have suggested, it must also be present in the 

 cane juice. 



If then an acetic acid fermentation played the part which I have indi- 

 cated above in the production of the " fruity" acid, it followed that a 

 slight acidification of cane juice with dilute sulphuric acid would effect 

 the same result, i. e. sulphuric acid being the strongest acid known 

 would turn out the fruity acid from whatever base it might be combined. 

 When however I added dilute sulphuric acid in the cold to the cane 

 juice I was not able to detect the presence of the fruity acid. At first 

 sight then it would appear as if the fruity acid was not present in the 

 juice. Remembering however that dunder is the residue of cane juice 

 we must also take into account the treatment which the cane juice 

 undergoes in the Boiling House, i. e., the heating with temper lime 

 in the cyphons and coppers. I accordingly heated the cane juice with 

 temper lime and then acidulated with sulphuric acid : the fruity smell 

 made its appearance and an extraction by means of petroleum ether 

 left behind a residue which had exactly the same smell as the fruity acid 

 extracted from the dunder. I think we may therefore conclude that 

 we have here to do with the same acid in each case, and my explana- 

 tion of the formation of this fruity acid in the dunder would therefore 

 be, that the fruity acid is present combined with some alcohol in the 

 cane juice, that on the treatment with lime, a decomposition known in 

 chemistry as " saponification" takes place, the lime salt of the acid is 

 formed with the simultaneous liberation of the alcohol and that this lime 

 salt of the acid on a subsequent acetic fermentation in the cane juice, 

 or if not here then in the dunder is decomposed, the fruity acid being 

 set free and acetate of lime being formed. As to the physical proper- 

 ties of the combination in which the fruity acid is originally present 

 in the cane juice, I am unable at present to say positively. Perhaps it 

 is present in the form of a wax or oil, and perhaps this would explain the 

 energetic measures which are required to decompose it. There is no 

 doubt that it could be decomposed direct by strong sulphuric acid without 

 the previous treatment with lime and heat but since this process is not 

 carried out in the Still House, and since an acetic fermentation cannot pos- 

 sibly work so energetically as strong sulphuric acid, it seems evident that 

 the treatment of the juice ivith lime plays an important and essential part 

 in enabling the fruity acid to be present in a form in which it may subse- 

 quently serve as a source of aroma. The fruity acid in whatever form 

 of combination it may be, is present in a volatile form. This seems to 

 me an important point Jbecause if the heating with lime be carried out 

 too energetically this volatile salt will be driven off in the form of 

 vapour, without being decomposed. That this is really able to take 

 place the following experiment proves. Some dunder was taken and 

 tempered to distinct alkalinity, in fact a considerable amount of alkal- 

 inity was present, and distilled, about a quart of liquid was used and it 

 was therefore quickly heated to boiling. The vapour was condensed, 



