180 



FUNCTIONS OF NUTRITION. 



varying proportions. Generally the glycocholate may be said to pre- 

 ponderate in the ruminant animals, taurocholate in the carnivora. In 

 dog's and cat's bile, the taurocholate exists alone. In human bile both 

 substances may be present ; sometimes one being the more abundant, 

 sometimes the other. According to some writers (Robin, Hardy, 

 Gorup-Besanez, Hoppe-Seyler) the taurocholate exists alone or in 

 greater quantity ; according to others (Bischoff, Lossen, Ranke) the 

 glycocholate is in larger proportion. In Jacobsen's case, sodium glyco- 

 cholate was invariably present, the taurocholate being less constant. 

 We have also found human bile to contain the glycocholate without 

 taurocholate. As the first of these substances is produced from the 

 second, by dehydration and separation of its sulphur, it is explainable 

 why the proportions of the two should vary from time to time. 



Mode of Secretion and Discharge of the Bile. As in man and 

 most animals the gall-bladder forms a lateral receptacle in which the 

 bile is wholly or partially stored up during a certain time, there are 

 two points which require separate investigation ; first, the manner and 

 rate of its secretion by the liver ; and secondly, the time and quantity 

 of its discharge into the intestine. 



In regard to its mode of secretion, the experiments of Bidder and 



FIG. 29. 



Schmidt were performed in the fol- 

 lowing manner : They operated by 

 tying the common bile-duct, and 

 then opening the fundus of the gall- 

 bladder, thus producing a biliary 

 fistula, by which the whole of the 

 bile was drawn off. By collecting 

 and weighing the fluid discharged 

 at different periods, they came to 

 the conclusion that the secretion 

 of bile never entirely ceases ; but 

 that it begins to increase within 

 two and a half hours after taking 

 food, to reach its maximum about 

 the twelfth or fifteenth hour. Other 

 observers have obtained different 

 results. Arnold found the quantity 

 largest soon after meals, decreasing 

 again after the fourth hour. Kol- 

 liker and Miiller found it largest 



DUODENAL FISTULA IN THE DOG. a. Stomach. , . ,, ... i . ,1 i 



b. Duodenum. c , c, c. Pancreas; its two ducts between the sixth and eighth hours. 



opening into the duodenum, one near the The bile is therefore a Continuous 

 orifice of the biliary duct. cl. the other a short -, . , -, 



distance lower down. e . silver tube passing secretion, but variable in quantity 

 through the abdominal wails into the duo- at different times i beinff, according- 



denum. 



to the majority of observers, most 

 abundant some hours after the commencement of digestion. 



As to its discharge into the alimentary canal, it is certain, in the first 



