B. W. Bull on Emulsine and its Composition. 81 



ed by evaporation, possesses an acid reaction, and on evaporation 

 leaves a gum-like acid uncrystallizable mass. This substance 

 contains nitrogen and is insoluble in alcohol and ether. It forms 

 insoluble salts with baryta and silver, and a soluble one with 

 magnesia, but could not be obtained in sufficient quantity for 

 analysis. The filtrate from the precipitate by acetate of lead 

 contains a large amount of organic matter, which, when the lead 

 is removed by sulphureted hydrogen, reacts quite neutral and 

 leaves upon evaporation a gum-like mass, which also contains 

 nitrogen. 



On one occasion, in the hope of obtaining a larger amount of 

 the above mentioned acid substance, I took a number of grammes 

 of freshly precipitated undried emulsine, thinking in this way to 

 avoid the formation of the insoluble compound left behind when 

 dried emulsine is redissolved, and the consequent loss of material, 

 but quite unexpectedly the resulting solution was not precipitated 

 on the addition of the lead salt. On the contrary, redissolved 

 dried emulsine gave invariably a precipitate with that substance. 



The behavior of emulsine towards acetate of lead can only be 

 explained by attributing it to the relation in which it stands to 

 the phosphate, a relation so delicate as to be disturbed or mate- 

 rially altered by merely undergoing a drying process over sulphu- 

 ric acid. In favor of this opinion is the fact of the increase of 

 inorganic matter in the insoluble portion remaining when dried 

 emulsine has been treated with water, and the corresponding de- 

 crease of the same in the solutions showing; that redissolved emul- 



O 



sine is unable to retain so large an amount of phosphates in solu- 

 tion as when first precipitated and undried, or in the state in 

 which it exists in an almond emulsion. The per-centage of the 

 phosphates present is very irregular and does not seem to be in- 

 fluenced by chemical proportions at all, but the average results 

 obtained confirm the above statement. The large amount of 

 these salts in the substance at present treated of, is but another 

 instance of their almost universal presence in all organized struc- 

 tures, as well as of the important, though it must be confessed, 

 slightly understood role which they play in the animal and veg- 

 etable economy. 



Upon distilling the alcohol from the liquid from which the 

 emulsine had been precipitated, the residue became gradually col- 

 ored, and at the end of the operation was quite dark. Evaporated 

 upon a water bath, it became a thick syrupy acid mass. Agitated 

 with ether, the latter became quite acid, and upon distilling the 

 ether, a yellow acid liquid remained in the retort, which by a 

 second treatment was obtained nearly pure and colorless. By 

 ueutralization with carbonate of zinc and concentration, distinct 

 quadrangular prismatic crystals were obtained, resembling lactate 

 01 zinc, but not in sufficient quantity for analysis. In the syrupy 



Second Series, Vol. V III, No. 22— July, 1 849. 1 1 



