GLANDS 147 



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 haematoxylin solution ; and, after washing this away, add a drop 

 of glycerin, and cover. This method is very generally useful for teased m* 

 scraped fragments of glandular structures. 



! 



(Figs. 97, 98 and 99) 



OBSERVE: 

 (L.) 



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

 gland, and least so in the pancreas.) 



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

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

 Also the thick connective tissue adventitia, especially demonstrable 

 in the pancreas.) 



3. The lobules. (These are formed by several acini, and are* 

 most typical in the parotid. It must be remembered that only one 

 plane is visible, and that there is little perspective.) 



4. The acini. (Note the lumina large in the submaxillary, 

 less so in the parotid, and least, and often difficult to make out, 

 in the pancreas. 



5. The blood-vessels, muscular and adipose tissue. (The 

 two latter are demonstrable only in the salivary glands, and do not 

 belong properly to the gland itself. The capsule of the pancreas, 

 in common with such structures in general, contains adipose tissue. 

 The abundant interacinous capillary plexuses of the pancreas 

 require the high -power for satisfactory demonstration.) 



(H.) 



6. The parenchyma. () The small but distinct shortened 

 columnar cells of the acini of the parotid. (Observe that they 

 are frequently so formed that the convexity of one cell fits into the 

 concavity of its neighbor. Where seen in transverse section, the 

 outline is a polygon. Note especially the change in the parenchy- 

 matous elements as the terminal duct merges into an acinus.) 



(6) The large, swollen cells of the mucous acini submaxil- 

 Im-y. (Observe the comparative clearness of the cells. They 

 contain a very delicate reticulum, and their nuclei are often 

 obscured and frequently seen to be placed at the junction of the 

 cells.) 



(c) The rounded, often polyhedral cells of the pancreas. 



