B. H. Chittenden — Ferments of Pineapple Juice. 301 



plan : a large \'olume of fi'eslily filtered juice was carefully neutral- 

 ized with sodium carbonate, and then saturated at the temperature of 

 the room with pure salt. The slight flocculent precipitate which re- 

 sulted was filtered off, washed with saturated salt-solution, then 

 dissolved in water and dialyzed in running water, putrefaction being 

 prevented by addition of thymol. After several days' dialysis, 

 though still containing some sodium chloride, a portion was tested 

 as follows : it had the appearance of a somewhat turbid fluid, as 

 though a separation had commenced to take place, but it could not 

 be filtered clear. On warming the mixture gently, the turbidity 

 showed a tendency to clear up somewhat. Subjected to careful 

 heating, the mixture appeared to show an increased turbidity at 65° 

 C, while at 72° C. there was a distinct and heavy turbity, but no 

 separation of flocks. As the temperature was raised, the turbidity 

 changed to a thick milkiness without, however, any appearance of 

 flocks even on boiling. The solution seemed perfectly neutral to 

 delicate test papers. By judicious addition of dilute acetic acid and 

 renewed heating, the milky fluid was finally made to yield a flocky 

 precipitate, in the filtrate from which no proteid reaction could be 

 obtained, thus indicating that the sodium chloride precipitate is 

 composed wholly of matter precipitable by heat. 



Tlie solution taken from the dialyzer showed strong proteolytic 

 action on blood fibrin. 



The remainder of the solution was dialyzed for one week lono-er 

 until nearly every trace of sodium chloride was removed, and again 

 tested. The fluid had a very milky appearance, but no distinct 

 separation of flocculent matter was seen. This heavy turbidity 

 cleared up somewhat on warming and disappeared completely on 

 adding a few drops of 20 per cent, salt-solution, also on the 

 addition of a drop or two of dilute nitric acid. The addition of 

 more nitric acid to the latter solution was followed by the reappear- 

 ance of a turbidity, which did not disappear by gentle heat, but 

 separated into flocks, not readily soluble in a large excess of nitric 

 acid. 



The reaction of the solution taken from the dialyzer was faintly 

 alkaline. Heated, the solution became distinctly turbid at 65°-70° 

 C. and quite opaque at 80" C, but without separation of flocks until 

 after persistent boiling. A drop of acetic acid, however, added to 

 the boiling fluid quickly caused a flocculent precipitate, the filtrate 

 from which was practically free from all trace of proteids. The salt- 

 free solution, although faintly alkaline, still showed strong pro- 

 teolytic power. 



