The Philippine Journal of Science 

 Table I. — Typical digestion experiment. 



1916 



No. of 

 BMk. 



Milk. 



CO. 



Water. 

 ee. 



Papain 

 ■olution. 



Papain. 





ee. 



mg. 



1 



25 



23 



2 



10 



2 



26 



21 



4 



20 



3 



26 



19 



6 



SO 



4 



26 



17 



8 



40 



S 



25 



15 



10 



60 



6 



25 



13 



12 



60 



7 



25 



11 



14 



70 



8 



25 



9 



16 



80 



9 



25 



7 



18 



90 



10 



25 



5 



20 



100 



11 



25 



25 











The milk and water were always measured into the flasks 

 and mixed by shaking. The enzyme solution was rapidly added 

 from a burette, the contents were well mixed by a few vigorous 

 shakes, and the flasks were at once placed in the thermostat. At 

 the expiration of exactly thirty minutes they were removed in 

 the same order, 20 cubic centimeters of ice water added to each, 

 and the flasks placed in melting ice to stop digestion. 



The contents of each flask were then successively washed 

 into a 500 cubic centimeter beaker, sufficient water being used 

 to give approximately 75 cubic centimeters of final volume. The 

 undigested protein was then precipitated by slowly adding 0.5 

 cubic centimeter of copper sulphate solution ( 60 grams per liter) , 

 followed by 0.5 cubic centimeter of glacial acetic acid, the 

 solution being vigorously stirred during precipitation. 



The contents of the beaker were now washed into 100 cubic 

 centimeter measuring cylinders and allowed to stand for a short 

 time to permit the curd to settle, after which they were filtered 

 through 11-centimeter ashless papers, which had been previously 

 numbered, dried at 100°, and weighed. It frequently happens 

 that filtration proceeds very slowly, in which case it is not 

 advisable to wait until all the liquid has passed through, but 

 is better to proceed with the washing. The curd is washed back 

 into the cylinders with distilled water warmed to about 60°, 

 and is thoroughly disintegrated by means of a rubber-tipped 

 stirring rod. The sediment now settles readily, and the solutions 

 filter rapidly. The undigested protein is washed three more 

 times in this manner to remove sugars and soluble digestion 

 products, gentle suction is applied to remove the surplus water, 



