84 B. W. Bull on Emulsine and its Composition. 



the slightest trace of acetic acid could be detected even by the 

 delicate test recommended by Bunsen, which consists in evapora- 

 ting to dryness in contact with caustic potash and arsenious acid. 

 The least trace of acetic acid is revealed by the formation of al- 

 carsin. The distillate was treated with carbonate of baryta in 

 excess, a part of which was dissolved and again distilled. The 

 distillate was neutral and odorless. The residue in the retort 

 was filtered from the excess of carbonate of baryta, and upon 

 concentration a small amount of crystals were obtained, which, 

 with a lens, appeared to be quadrangular prisms. Upon decom- 

 posing their solution by the addition of sulphuric acid and gently 

 warming, the aromatic smell was again perceived. 



The residue from the first distillation was sour, but the actual 

 amount of acid present was so small that an attempt at analysis 

 would have been useless. It is certain however that during: the 



fermentation, no free acetic acid was formed, and attempts to find 

 it in combination were also fruitless. 



The coagulum formed contains a large amount of oil ; it is en- 

 tirely insoluble in dilute acetic acid, is dissolved by caustic alkalies 

 with evolution of ammonia. It is insoluble in carbonated alkalies, 

 and is decomposed by treatment at a very gentle heat (30° to 

 40° C.) with a moderately strong solution, with escapement of 

 ammonia. As the alkaline solutions of this and of the precipi- 

 tate by acetic acid are not thrown down by alcohol, it is not 

 necessary that they should be absent from the fluid before pro- 

 ceeding to precipitate the emulsine. The fermentation takes place 

 without any visible evolution of gas, unless allowed to remain 

 till the liquid begins to putrefy. 



The ashes from the syrupy liquid from which the alcohol had 

 been distilled have a strong alkaline reaction, and contain a large 

 proportion of potash. 



The above facts lead to the conclusion, that the souring of an 

 emulsion of sweet almonds has a very close resemblance to that 

 of ordinary milk. The presence of lactic acid in a state of com- 

 bination has been proved in the sour liquid, and there can be no 

 doubt that the free fixed acid formed is also the same. The con- 

 version of the sugar into lactic acid and the union of this acid 

 with the bases which had held the caseous substance in solution, 

 accounts for the appearance of the coagulum, and the subsequent 

 non-appearance of a precipitate of acetic acid, as soon as sufficient 

 acid has been generated by the fermentation, to precipitate all this 

 caseous matter from its union with the alkalies. 



I come now to the elementary composition of emulsine, the 

 analysis of which was rendered very difficult by the large amount 

 of inorganic matter with which it is encumbered, and which will 

 account for the otherwise too great variation in the results. Not- 

 withstanding this disadvantage they are sufficiently constant to 



