ON PANCREATIC PROTEOLYSIS. 205 



true that fresh bile usually reacts alkaline to red litmus paper, 

 but we have been unable to find any statements in the litera- 

 ture justifying the assumption that sodium carbonate is 

 present. Indeed, some comparatively recent observations 

 made by Jolles * show that the bile of oxen, dogs, and pigs, as 

 well as human bile, reacts acid to phenolphthalein. This 

 obviously does not imply the presence of free acid, although 

 some free fatty acids may be present, such as stearic, palmitic, 

 and oleic acids.f Jolles, indeed, concludes from his experi- 

 ments that the fresh bile of man and the above-mentioned 

 animals is not an alkaline or neutral fluid, but possesses a 

 weak acid reaction. He finds, for example, on titrating ox- 

 bile with a decinormal solution of potassium hydroxide, using 

 phenolphthalein as an indicator, that on an average 1 gram of 

 bile requires 0.546 milligram KOH to neutralize the free 

 acids or acid-salts present. It is to be noted, likewise, that 

 the acidity varies with different samples of bile, the extremes 

 in ten experiments being 0.483 and 0.633. In pig's bile the 

 average acidity was somewhat higher, 0.86 milligram KOH 

 being required to neutralize the acid salts of 1 gram of bile. 

 Further, the variations in acidity were much greater, the 

 extremes hi eight observations being 0.56 and 1.56. In dog's 

 bile, on the other hand, the acidity (in one experiment) was 

 only 0.42. Human bile, however, was much more strongly 

 acid, 1 gram of bile requiring on an average 2.36 milligrams 

 of KOH to neutralize the acid salts. These observations, 

 which have an important bearing upon the subject under 

 consideration, we are able to confirm in a general way through 

 a large number of determinations made in this laboratory J 

 upon various kinds of bile. Only in rabbit's bile was there a 

 failure to detect a measurable amount of acidity. Cat's bile, 

 however, showed an acidity equal to only 0.23. Now, it is 

 obvious from these statements that bile (excepting possibly 

 rabbit's bile) cannot contain any alkali as strong as sodium 



* Jolles, A., Archir f. d. ges. Physiol., 1894, Ixvii, p. 1. 



t Lassar-Cohn, Zeitschr. f. physiol. Chemie, 1893, xvii, p. 607. 



} By Ernest W. Brown. 



