CHAPTER IX. 



PANCREATIC JUICE. 



SECOND only to the stomach in importance as a digestive cavity, 

 is the duodenum, into which the copious secretion of two of the 

 largest glands of the body the pancreas and the liver is 

 poured. 



The pancreas is a large compound sacculated or acinous gland, 

 being composed of numerous irregular packets of gland tissue 

 attached by its lateral branchlets to the main central duct. The 

 saccules are rather elongated, but have the same general con- 

 struction as those of the serous salivary glands already described. 

 A single layer of irregular or slightly conical cylindrical cells in 

 the saccule, shows a difference of structure in its central and 

 peripheral sides, so that an external or homogeneous zone, and 

 an internal granular zone may be distinguished. Each zone cor- 

 responds to one-half of the cells, the clear half being next the 

 boundary, and the granular half next the lumen of the saccule. 

 The relative width of these zones varies with the digestive pro- 

 cess, so that the nuclei which are situated between them some- 

 times appear to be in the outer clear zone, and sometimes in the 

 inner granular zone. The outer zone colors readily with car- 

 mine, whilst the inner zone remains unstained. 



The large duct which passes down the axis of the gland, re- 

 ceiving tributaries on all sides, is surrounded with a layer of 

 loose connective tissue whicli forms an outer coat. The proper 

 coat of the duct is composed of elastic tissue, lined by a single 

 layer of cylindrical epithelium. 



Collection of Pancreatic Juice. From a temporary 

 fistula the secretion of the pancreas can be obtained in sufficient 

 quantity to determine its character and properties. 'A permanent 

 fistula is established with difficulty, and the secretion soon alters 



