160 PRACTICAL MICROSCOPY. 



Also the thick connective-tissue adventitia, especially demonstrable in 1 

 the pancreas.) 



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

 only in the parotid at least they only here appear well formed. 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. The 

 abundant inter-acinous capillary plexuses of the pancreas require the 

 high power for satisfactory demonstration.) 



(H.) 



6. The parenchyma, (a) 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 con- 

 cavity of its neighbor. Where seen in transverse section, the outline 

 is a polygon. Nbte especially the change in the parenchymatous 

 elements as the terminal duct merges into an acinus.) 



(#) The large, swollen cells of the mucous gland submaxil- 

 lary. (Observe the comparatively 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. (They 

 resemble the parotid elements, although smaller and less granular.) 



