USE OF THE BILE IN INTESTINAL DIGESTION. 



177 



its rate is thus greatly influenced by the stage of the digestive process ( which 

 is the less to be wondered at, when it is remembered that the secretion is 

 formed from blood that is charged with newly-absorbed and imperfectly- 

 assimilated matters), the excrementitious character of the secretion requires 

 that its elimination shall be constantly going on to a certain degree ; but a 

 receptacle is provided in Man, as in most others among the higher animals 

 whose digestion is performed at intervals, for the storing up of the fluid 

 until it can be usefully employed in that process. The intestinal orifice of 

 the ductus choledochus is closed by a sort of sphincter; and the fluid secreted 

 during the intervals of digestion, not being propelled with a force sufficient 

 to dilate this, flows back into the gall-bladder, which dilates to receive it. 

 The presence of food, and especially of the acid products of gastric digestion, in 

 the duodenum seems to excite the walls of the gall-bladder and of the biliary 

 ducts 1 (which contain a large quantity of non-striated muscular fibre), to a 

 contraction sufficiently powerful to propel their contents into the intestine, 

 in spite of the opposition of the sphincter; but whether this takes place 

 through a reflex action of the nervous system, or through the direct stimu- 

 lation of the muscular coat of the duct by the passage of alimentary matters 

 over its orifice, we have at present no means of satisfactorily determining. 

 It will be recollected that the gall-bladder is usually found distended with 

 bile, in cases of death from starvation ( 79), notwithstanding the diminu- 

 tion in the amount actually secreted. Of the bile which is poured into the 

 intestinal tube, by far the greater proportion seems to be reabsorbed ( 129), 

 or at least to be so altered that the presence of the biliary acids can no 

 longer be recognized. 



126. Besides the biliary and pancreatic secretions, there is poured into 

 the Intestinal canal a fluid secreted in its own walls, which has received the 

 designation of Succus Entcricus. The secretion of this fluid is partly the 

 function of the Glands of Briiuner, 

 which are small racemose clusters of 

 follicles 2 (Fig. 73), imbedded in the 

 walls of the duodenum, extending also 

 to the commencement of the jejunum, 

 and partly of the follicles of Lieber- 

 kiihn, with which the intestinal canal 

 is furnished throughout its entire 

 length. These are straight narrow 

 cseca, standing side by side, with a 

 little adenoid intervening substance 

 (except where the Peyerian bodies lie 

 amongst them), and corresponding in 

 length with the thickness of the mu- 

 cous membrane. Their orifices are 

 seen in the interspaces between the 



Villi, Where they are SO closely set tO- Portions of one O f Brunner's Glands, from the 



gether as to seem like the apertures of Human Duodenum. 



FIG. 73. 



1 Bernard and Kuthe (Canstatt's Jahresbericht, 1861, p. 131) found that touching 

 the point of entrance of the biliary duct into the intestine with an alkaline fluid had 

 little or no effect, whilst brushing it lightly over with an acid solution immediately 

 caused a discharge of bile to take place. 



2 Puky Akos and Schlemmer (Wien Aktid. Sitzungsber., 1869, Band Ix, p. 31 

 and p. 169) regard these glands as belonging rather to the tubular than to the race- 

 mose type, whilst Schwalbe considers them to be intermediate to both. See Max 

 Schultze's Archiv, Band viii, p. 92. Toldt (Mittheil. der artz. Vereins in Wien, 

 Band i, p. 33) holds them to be racemose glands. 



