550 SPECIAL HISTOLOGY. 



racemose glands of 0-06-0-08 of a line with vesicles of 0-016-0-02 of 

 a line, and a less fatty epithelium, are situated in considerable numbers ; 

 whether they are mucous glands analogous to those of the biliary ducts, 

 or parts of the pancreas itself, I cannot say. The pancreas possesses 

 the ordinary investing tissue of the glands, with more or less abundant 

 fat-cells, in which the vessels and nerves of the gland are distributed. 



Fig. 225. 



The former present exactly the same relations as in the parotid, except 

 that the lymphatics appear to be more numerous ; the latter would seem 

 only to accompany the vessels and arise from the sympathetic, possess- 

 ing fine, and a few moderately thick tubules. The secretion of the pancreas 

 is normally perfectly fluid, only accidentally containing formed constitu- 

 ents, as detached epithelium of the glandular vesicles and of the ducts. 



The development of the pancreas commences by the formation of a 

 diverticulum of the posterior wall of the duodenum and in its further 

 progress, exactly resembles the salivary glands, except that the rudiment 

 of the gland forms, from the first, a more compact mass and thence is 

 not so readily made out in detail. 



The examination of the pancreas presents no difficulties, except that, 

 in Man, the fat in the epithelial cells of the glandular vesicles offers 

 some impediment and therefore the pancreas of Mammalia (Rabbit, 

 Mouse), which usually contains less fat, should be made use of. The 

 glandules in the ducts are best rendered visible by acetic acid. 



[Literature. J. G. Wirsung, "Figura ductus cujusdam cum multi- 

 plicibus suis ramulis noviter in pancreate observati," Padov., 1643 ; J. 



FIG. 225. Vessels of the pancreas of the Rabbit, magnified 45 diameters. 



