ON PANCREATIC PROTEOLYSIS. 199 



possible, and when from dogs or cats it was usually obtained 

 through a temporary biliary fistula. 



In arranging the experiments each digestive mixture in a 

 series was made to contain the same volume of pancreatic 

 juice for each gram of dried fibrin usually 10 c.c. or 20 c.c. 

 according to the strength of the juice with a total volume 

 of 50 c.c. ; water, bile, bile salts, acid, alkali, etc., being added 

 in the proportions necessary to give the percentages specified. 

 All the mixtures of a series were placed in the same water-bath 

 at 40 C., all stirred equally, and when digestive action was 

 sufficiently advanced the undigested residues were collected on 

 weighed filters, previously dried at 110 C, in glass-stoppered 

 weighing bottles, and washed thoroughly with hot water, and 

 lastly with alcohol and ether. On drying the papers with their 

 contents at 110 C. until of constant weight the proportion of 

 undigested matter was readily ascertained, from which the 

 relative proteolytic action of the several mixtures was easily 

 calculated. It is hardly necessary to add that all the mixtures 

 of a given series were kept at 40 C. for the same length of 

 tune, usually 2-4 hours, it being our aim to have the proteid 

 material in the control mixture digested to the extent of 40- 

 60 per cent. 



II. INFLUENCE OP FRESH BILE ON THE PROTEOLYTIC 



ACTION OP THE PANCREATIC ENZYME IN NEUTRAL 



SOLUTION. 



The following quantitative results show the extent and 

 character of the influence exerted by bile from various sources 

 upon neutral solutions of trypsin: 



Experiment 1. Fig's bile. Neutral extract of pig's pancreas. 



Per cent of Bile. Undigested Residue. Fibrin Digested. Relative Proteolytic Action. 



0.4382 gram 66.18 per cent 100.0 



0.4477 65.23 98.3 



1.0 0.4891 61.09 90.9 



3.0 0.4922 50.78 90.3 



5.0 0.4616 53.84 95.8 



10.0 0.4426 56.74 99.2 



15.0 0.4204 67.96 103.1 



20.0 0.4052 69.48 105.8 



25.0 0.4206 67.94 103.1 



