THE PANCREAS. 159 



THE PANCREAS. 



The histology of the pancreas is, in general, that of a true serous 

 ^gland e. g., the parotid. It has been called by physiologists the 

 abdominal salivary gland. 



The cells, constituting the parenchyma, are somewhat smaller; the 

 lobules less regular in size and form; and the lumen of the acini 

 much less easy of demonstration, in an ordinary hardened section, 

 than the same in the parotid. The vascular supply is also more 

 abundant. 



The branches of the pancreatic duct are provided with a very 

 thick adventitia, are lined with short columnar cells, and seldom 

 present the dilatation, which generally occurs in a serous gland, on 

 entering the lobule. 



PEACTICAL DEMONSTRATION. 



PAKOTID AND SUBMAXILLARY GLANDS, AND THE PANCREAS. 



The tissue must be fresh, divided in small pieces not larger than 

 a quarter of an inch cube and hardened by placing in ninety-five per 

 cent alcohol for twelve hours, after which fresh spirit should be sub- 

 stituted. If, after the lapse of another twelve hours* the tissue should 

 not be sufficiently firm, it should be placed in a small quantity of ab- 

 solute alcohol for three hours. Sections should be made immediately 

 after hardening as more prolonged action of the strong spirit will 

 cause the tissue to contract. 



Sections may be cut with or without a simple microtome the 

 desideratum being thin, rather than large cuts. 



Stain lightly with haema., and deeply with eosin. 



After sections of hardened tissue have been examined, the glandular 

 parenchyma may be profitably studied in teasings from tissue which 

 has been in Miiller twenty-four hours. Wash the teasings on the 

 slide with a liberal supply of water, removing the same from time to 

 time with blotting paper. Add a drop of haema, solution; and, after 

 washing this away, add a drop of glycerin, and cover. This 

 method is very generally useful for teased or scraped fragments of 

 glandular structures. 



(Figs. 106, 107, and 108.) 

 OBSERVE: 

 (L.) 



1. The connective tissue. (Most abundant in the parotid, and 

 least so in pancreas. ) 



2. The ducts. (Note the flattening of the lining columnar 

 cells, as the ducts approach the acini, until mere scales result. 



