186 FUNCTIONS OF NUTRITION. 



The biliary matters, therefore, are either so decomposed in the 

 intestine as to lose their distinctive reactions, or they are reab- 

 sorbed in some form by the mucous membrane, and again intro- 

 duced into the circulation. It seems highly probable that they are 

 reabsorbed. In the experiments of Bidder and Schmidt, above quoted, 

 this point was examined by elementary analysis of the fecal ingredi- 

 ents. In dog's bile the only or preponderating biliary salt is the 

 taurocholate, which contains sulphur. If the taurocholate had been 

 simply decomposed or transformed in the intestine, so as to be undis- 

 tinguishable by Pettenkofer's test, its sulphur ingredient would still be 

 found in the feces. But in the animal subjected to experiment, the 

 sulphur ingredient of the bile secreted during five days would amount 

 to 2.364 grammes ; while only 0.385 gramme of sulphur was contained 

 in the feces for the same time, and of this only 0.155 gramme could 

 have been derived from biliary substances. That is, not more than 

 one-fifteenth part of the sulphur originally present in the bile could 

 be detected in the feces. 



A further evidence of the reabsorption of biliary matters from the 

 intestine is furnished by the experiments of Schiff,* which were con- 

 ducted on a different plan. This observer found that, under ordinary 

 conditions, less pressure is required to make a fluid pass from the 

 hepatic duct into the gall-bladder than to force it into the intestine. 

 Unless, therefore, the pressure in the gall-bladder be increased, either 

 by distention or by muscular contraction, it passes into the gall-bladder 

 more readily than into the intestine ; and a cystic fistula, if kept freely 

 open, will be sufficient to discharge externally nearly all the secreted 

 bile. Schiff demonstrated this by establishing in the same animal a 

 fistula of the gall-bladder and one of the duodenum. So long as the 

 cystic fistula remained open no biliary matters, or only insignificant 

 traces of them, could be found in the duodenum. 



On the other hand, w T hen the cystic fistula was closed, the bile passed 

 through the common duct into the intestine, thus maintaining the 

 animal in a healthy condition. At any time, by opening the fistula and 

 emptying the gall-bladder, the rate of secretion might be ascertained. 



Schiff 's observations show that by leaving open the fistula, and thus 

 diverting the bile from the intestine, its rate of secretion is at once 

 diminished ; so that at the end of twenty-four hours, if the influence of 

 digestion be eliminated, it is reduced to a minimum, which afterward 

 continues with only insignificant fluctuations. But if the fistula be 

 closed for some hours, the quantity of bile again rises to its normal 

 standard. 



The same observer obtained similar results by making, in the dog, a 

 duodenal fistula, through which a canula was introduced into the com- 

 mon bile-duct. The canula had a lateral opening near its end, which 

 might be left open or closed by shifting the position of an inner tube 



* Arclriv fur die gesammte Physiologic. Bonn, 1870, p. 598. 



