103 



alimentary substance, and to prolong its stay within it, that it may re- 

 main the longer exposed to the action of these fluids. 



The duodenum is, in fact, almost entirely uncovered by the peritoneum, 

 a serous membrane, which like all those that line the inside of the great 

 cavities, and reflect themselves over the viscera which they contain, by 

 furnishing them external coverings, admits but of little extension, and 

 seems to stretch, when these viscera become dilated, only by the unfold- 

 ing of its numerous duplicaiures. Fixed by a rather loos* cellular tissue 

 to the posterior side of the abdomen, the duodenum is susceptible of such 

 dilatation, as to equal the stomach in size, as is sometimes seen in open- 

 ing dead bodies. Its curvatures depend on the neighbouring organs, and 

 seem almost invariably fixed; lastly, numerous valyulse line its inner sur- 

 face, so as to add to the friction, and to increase the extent of surface, and 

 thereby the number of absorbents destined to take up the chyle separated 

 in the duodenum, from the excrementitious part of the food, by the action 

 of the fluids poured into it, from the united ducts of the liver 'and pan- 

 creas*. 



XXVI. Of the Bile and of the Organs which serve for its secretion. The 

 bile is a viscous, bitter, and yellowish fluid, containing a great quantity 

 of water, of albumen to which it owes its viscid condition, and oil to 

 which the colouring and bitter principle is united. Soda, to which the 

 bile owes the property of turning vegetable blues to a green colour, phos- 

 phates, carbonates, and muriates of soda, phosphates of lime, and of am- 

 monia j and, lastly, as some say, oxide of iron, and a saccharine substance 

 resembling the sugar of milk. This fluid, which the ancients Looked upon 

 as animal soap, fitted for effecting a more intimate mixture of the alimen- 



* The muscular coat of the duodenum is thicker than that of the small intestines, 

 the base of the villi of the mucous tunic is more thickly set with glandular follicles, 

 and the wjiole duodenum presents a more vascular appearance than any other portion 

 of the intestines. 



The experiments of Dr. PROUT on chyme, taken from the duodenum, exhibit the 

 following 1 results : 



1. VEGETABLE FOOD. 



Composed of a semi-fluid, opake, yellowish white part, having- mixed with it an- 

 other portion of similar colour, but of firmer consistence. It coagulated milk com- 

 pletely. 



AVater, 86-5 



Chyme, &c g. 



"Biliary principle, . . . , 1-5 



Vegetable gluten, .... 5. 



Saline matter, ... .7 



Insoluble residuum, ... -2 



100 

 2. ANIMAL FOOD. 



More thick and viscid than chyme from vegetable food, and its colour more inclining: 

 to red. Did not coagulate milk. 



Water, 80- 



Chyme, &c. . 

 Albuminous matter 

 Biliary principle, 

 Saline matters, 

 Isoluble residuum, 



15-8 



1-3 



1-7 



7 



5 



100 



