194 INFLUENCE OF BILE AND BILE SALTS 



rapidly as an alkaline solution, provided the content of alkali 

 was not too great. If, however, the proportion of lactic acid 

 was raised to 0.05 per cent, then bile and sodium chloride 

 were without avail in stimulating proteolysis. Experiments 

 made by the writer * some years ago likewise tended to show 

 that the presence of bile in a pancreatic extract containing 

 combined salicylic acid may increase somewhat the rate of 

 trypsin proteolysis over that of the acid mixture alone. It 

 was also shown at the same time that the addition of bile, 

 even to the extent of 10 per cent, to neutral or alkaline 

 pancreatic juice modifies only slightly the rate and extent of 

 proteolysis ; under some conditions inducing a slight stimula- 

 tion and under other conditions a more marked inhibition of 

 proteolysis. It was likewise observed that the deleterious 

 action of combined hydrochloric acid upon trypsin proteolysis 

 was not overcome by the addition of bile. A few experiments 

 reported by Martin and Williams f have also tended to indi- 

 cate that bile and bile salts may stimulate somewhat the rate 

 of pancreatic proteolysis. 



A careful survey of the results, and of the conditions under 

 which the results were obtained, recorded up to this time, led 

 the writer to the conclusion that the addition of bile to a 

 neutral or alkaline pancreatic juice causes but little change in 

 its proteolytic action. Some slight stimulation may be pro- 

 duced, but there is no convincing proof that this is of constant 

 occurrence or sufficient in degree to possess much physiological 

 significance. We have been more inclined to the view that 

 while the presence of bile hi the intestine may be of primary 

 importance for the assimilation of fats, its action upon trypsin 

 proteolysis is chiefly negative; i. e., it neither retards nor 

 stimulates proteolysis to any very great degree, under ordinary ' 

 conditions. Recently, however, another paper \ bearing on this 

 subject has appeared, which renders necessary a reconsideration 



Chittenden and Cummins, Influence of Bile, Bile Salts, and Bile Acids 

 on Amylolytic and Proteolytic Action, Amer. Chem. Journal, 1885, vii, p. 50. 

 t Martin and Williams, Proceedings of the Royal Society, 1890, xlviii, p. 160. 

 t Rachford and Southgate, Medical Record, 1896, xlviii, p. 878. 



