107 



sertion of its duct, into that which comes from the liver. Its inner mem- 

 brane is soft, fungous, plicated, and always covered with the mucus, se- 

 creted by the glandular criptae which it contains. This mucus defends 

 the gall bladder against the action of the bile which it contains. The al- 

 most parallel course of the hepatic and cystic ducts, the acute angle at 

 which they meet, renders it difficult to account for the passage of the 

 bile into the gall bladder. It appears, that when the duodenum is empty, 

 the bile regurgitates, in part, from the hepatic duct in the gall bladder, 

 collects within it, becomes thicker and yellower, and requires a greater 

 degree of bitterness. Consequently, the use of the gall bladder, is to serve 

 as a reservoir to a portion of the bile, whiclj, by remaining within it, is 

 improved in quality, acquires consistence and bitterness, and is heighten- 

 ed in colour, by the absorption of its fluid parts*. 



XXVII. The irritation produced on the parictes of the duodenum, 

 when distended by the chyme, is propagated to the gall bladder, by the 

 cystic and common ducts. Its parietes then contract, and oblige the bile 

 to flow, along this cystic duct into the ductus commimis choledochus. 

 The pressure of the distended intestines on the gall bladder, favours the 

 excretion of bile. The hepatic bile is also more abundantly poured into 

 the duodenum during digestion, from being secreted in greater quantity 

 by the liver, which participates in the irritation affecting the organs of 

 digestion, and secretes a greater quantity. The cystic and hepatic bile, 

 mixed in the ductus communis choledochus, undergoes a change before 

 entering the duodenum, by uniting with the fluid of the pancreas. The 

 excretory duct of the pancreas, a glandular organ, which, in structure, 

 bears so great an analogy to the parotid glands, thatsonje physiologists, 

 assuming an identity of functions, have called it the abdominal salivary 

 gland, joins the biliary duct, before the latter c>pens in the duodenum, 

 after having insinuated itself obliquely between the coats of that intes- 

 tine. It arises within the pancreas, from<t great number of radicles 

 which join it, like the feathers of a quill t a common trunk. Its calibre 

 increases in size as it approaches the l^ge end of the pancreas, situated 

 on the right, in the concavity of the pecond curvature of the duodenum. 

 Nothing precise is known, with regard to the nature of the pancreatic 

 fluid ; the striking resemblance of the pancreas to the salivary glands 

 leads to a presumption, that t^s fluid bears considerable analogy to the 

 saliva. The quantity of fluid secreted by the pancreas is likewise 

 unknown, but it must be considerable, if one may judge from the great 

 number of nerves and vessels which pervade its glandular tissue, and its 

 quantity is, most probably, increased by the irritation of the food in the 

 duodenumf. 



* See, in the cliapteron secretion, the laws which that function obeys. Copland. 



\ Opinions are various respecting the quantity of the secreted fluid which the pan- 

 creas yields. AUTEXIUETII reckoned the quantity at nine ounces tiie twenty-four 

 hours. It has been generally supposed that this secretion is considerably augmented 

 At the time that the chyme flows into the duodenum ; and the intimate connexion 

 existing 1 between the ganglial nerves, supplying- these viscera, favours the conclusion. 

 MAGENDIE, however, rejects this inference, and inserts, without stating the grounds 

 of his opinion, that the flow of the pancreatic juice is least abundant during digestion. 



The disordered functions of this organ appear to be very essentially concerned in 

 the production of some diseases which are too often referred entirely to the stomach 

 and small intestines, which, no doubt, become consecutively deranged from this cause ; 

 or, if the actions of the pancreas be not primarily diseased, a co-existent disorder may be 

 present in these allied viscera, and be equally the result of one cause. Copland. 



