288 H. H. Chittende7i — lerments of Pineapple Juice. 



the albumin was in part composed of insoluble antialbumid-like 

 matter, especially when the digestions were carried on in acid or 

 neutral media. The method, however, afforded a fairly accurate 

 means of measuring the proteolytic power of the ferment, as con- 

 tained in pineapple juice, while the greater resistance of coagulated 

 albumin as compared with blood fibrin seemed to offer advantages 

 in the way of accuracy. 



Experiment I. — The pineapple juice employed had an acidity 

 equal to 0-445 per cent. HCl,* requiring 13 c. c. of a 5-0 per cent, 

 solution of Na^COg to neutralize 100 c. c. The 10 grams of moist co- 

 agulum used in each digestive mixture contained 1*3G33 grams of 

 dry albumin (at 110° C). The mixtures were warmed at 40° C. for 

 3^ hours. 



Per cent. 

 Pineapple Juice. Reaction. Undissolved albumin. digested. 



A 100 c. c.f natural acidity 0'8932 gram 345 



B 100 neutralized 0-8187 400 



Experiment II. — The acidity of the pineapple juice employed 

 was equal to 0-507 per cent. HCl. Necessary to neutralize 100 c. c, 

 14*7 c. c. of a 5*0 per cent, solution of Na^CO^. Weight of dry 

 albumin equivalent to the 10 grams of moist coagulum used in each 

 mixture, 1-3302 grams. The digestions were carried on at 40° C. for 

 2 hours. 



Per cent. 

 Pineapple juice. Reaction. Undissolved albumin. digested. 



A 100 c. c. natural acidity 1-0536 grams 20-8 



B 100 neutralized 0-9355 29-7 



Experiment III — The acidit}^ of the pineapple juice was not 

 accurately determined. 15 c. c. of a dilute solution of sodium carbo- 

 nate were required to neutralize 100 c. c. of juice. The weight of 

 dry albumin contained in the 10 grams of moist coagulum used in 

 the digestions was 1-4583 grams. The mixtures were warmed at 

 40^ C. for 5^ hours. 



From these results, it is seen that full 40 per cent, or more of 

 coagulated egg-albumin can be converted into soluble products by 

 the pineapple ferment, under the conditions of the above experi- 



* Determined by titration with a standard solution of ammonium hydroxide, 

 f Plus the amount of sodium carbonate solution required for neutralization in B, and 

 of water to make an equal dilution in A. 



