XV.] SALIVARY GLANDS AND PANCREAS. SALIVA. 157 



between the mucous cells and the membrana 

 propria. 



d. The epithelium of the small ducts consists of 

 a single row of slender columnar cells, the 

 inner borders of which apparently coalesce 

 and form a distinct ring bounding the lumen: 

 there is no such distinct boundary to the 

 outer (circumferential) part of the cell, which 

 especially in haematoxylin specimens has a 

 well-marked- striation. Each cell contains 

 an oval nucleus, situated a little on the inner 

 side of the centre of the cell 



3. Take a small piece of a dog's submaxillary gland 

 which has been for three to six days in a 5 p. c. 

 solution of neutral ammonium chromate, and 

 tease it out in the same fluid. Observe the 

 isolated mucous and demilune cells, noting in 

 the mucous cells that the deep-seated end, in 

 which the nucleus lies, is prolonged into a process, 

 and that this, together with a varying amount 

 of the cell-substance around the nucleus, is more 

 granular and opaque than the rest of the cell. 

 The cell-network may also be obvious. 



4. Examine a mounted specimen of a dog's sub- 

 maxillary gland which has been taken after 

 prolonged secretion 1 . Observe under a high 

 power that 



1 In a dog under morphia and chloroform the chorda tympani (or 

 chorda tympani and sympathetic) is stimulated with a fairly strong 

 interrupted current for alternate minutes during six hours about. 



