294 JR. H. Chittenden — Terments of Pineapple Juice. 



peratures for 2\ hours, the juice having been first brought to the de- 

 sired temperature prior to the addition of the albumin. 



Although in this experiment, the proteolytic action of the juice, 

 for some reason, was not as great as usual the results show in a 

 general way that the activity of the ferment increases with the rise 

 in temperature up to 56° C. Further, that the ferment is active at 

 comparatively low temj^eratures, although there is a striking differ- 

 ence (nearly 50 per cent.) in activity between the two extremes, viz: 

 at 12'' and 56° C. That this peculiar ferment is truly more active at 

 50°-60° C. than at 30°-40° C, under the above conditions, is con- 

 firmed by the two following experiments : 



Experiment XII. — The weight of dry albumin equivalent to the 

 10 grams of moist coagulum used in each digestion was 1-2937 

 grams. The several portions of neutralized pineapple juice were 

 brought to the required tempei'atures in carefully regulated water- 

 baths, and when the desired point was reached the albumin loas at 

 once added and the mixtures kept at the stated temperatures for two 

 hoiii's, after which, as in the other experiments, the imdissolved 

 albumin was filtered off, washed, dried and weighed. 



Experiment XIII. — This experiment was conducted in essentially 

 the same manner as the preceding, but at different temperatures. 

 The weight of dry albumin equivalent to the 10 grams of moist 

 coagulum used in the individual digestions was 1-3710 grams. The 

 ferment was allowed to act on the albumin for two hours at the re- 

 spective temperatures. In this experiment, duplicate digestions were 

 made and the results are interesting as showing about how much 

 variation may be expected from the errors naturally incidental to 

 methods of this character. 



