DIGESTION. 183 



over 1100 grammes per day. Ranke,* in his case of human biliary 

 fistula, obtained a result not essentially different. The patient weighed 

 only 47 kilogrammes ; the average quantity of bile discharged in twenty- 

 four hours being 652 grammes, the maximum 945 grammes. In a man 

 of 65 kilogrammes' weight this would correspond, for the average, to 

 902 grammes, and for the maximum to 1307 grammes. The entire 

 quantity of bile, therefore, for a man of medium size, is evidently not 

 far from 1000 grammes per day. This contains about 30 grammes of 

 solid ingredients. 



Physiological Action of the Bile. Notwithstanding the well-marked 

 character of the bile, and its frequent investigation by competent ob- 

 servers, its physiological action remains extremely obscure. We can 

 state only a few points, which embrace nearly the whole of our pos- 

 itive knowledge in regard to it. 



In the first place, the bile is present in all vertebrate animals without 

 exception, and is discharged from the biliary duct into the intestine 

 near its upper extremity. This shows that the secretion is, in some 

 way, of fundamental importance, and also that it has a probable con- 

 nection with the digestive functions. 



But if the bile be tested for its digestive influence on the alimentary 

 substances, it does not exhibit any distinct properties in this respect. 

 A diastatic action on starch, which was attributed to it by "Wittich, 

 has been found wanting by others, and according to Ewald is of 

 inconstant occurrence, and never well marked in character. Its action 

 on fatty substances is but little more characteristic. It certainly has 

 the property of dissolving fats to some extent, both in the free form 

 and when saponified ; and such solvent power belongs also to a watery 

 solution of the biliary salts. But by far the greater part of the fatty 

 substances in digestion are absorbed in the emulsioned form, without 

 solution or saponification ; and, according to Hoppe-Seyler,f the quan- 

 tity of oily matter which the bile can dissolve is far below that absorbed 

 from the intestine. A direct emulsifying agency cannot be attributed 

 to the bile, since, when shaken up with oil, its emulsive effect is so in- 

 complete and temporary as to be practically without importance. It 

 has been thought to have an indirect action in this respect, when the 

 fats are partially acidified and saponified by the pancreatic juice, by 

 dissolving the saponified portion, and thus facilitating the emulsion of 

 the remainder. But emulsion takes place so instantly and completely 

 by the contact of oil with pancreatic juice, when no bile is present, that 

 its normal share in the process can hardly be a large one. As regards 

 the albuminous matters, there is no evidence that the bile exerts upon 

 them any specific action. 



Another influence regarded as belonging to the bile is that of excit- 

 ing the muscular action of the intestine, and thus serving as a stimulus 



* Physiologic des Menschen. Leipzig, 1872, p. 284. 

 f Physiologische Chemie. Berlin, 1878, p. 315. 



