XX] SALIVAKY GLANDS 157 



bursting, the cells become transparent, their outlines and nuclei 

 come into view. If acetic acid 1 p.c. is used instead of dilute 

 HC1, the nuclei will be more shrunken and the cells less trans- 

 parent. 



3. Section of serous gland. (Parotid of cat, or 

 sub-maxillary gland of rabbit. Alcohol ; hsematoxylin.) 

 Observe 



a. Under a low power, 



The lobules of varying size, separated from one 

 another by connective tissue. 



The alveoli, appearing as small roundish or short 

 tubular bodies, closely aggregated together ; each will 

 be seen to consist of a group of cells surrounded by 

 a small amount of connective tissue. (The terminal 

 branching tubes, the sections of which are here called 

 alveoli, may be so closely pressed together in the 

 process of hardening that at first sight they have the 

 appearance of continuous masses of cells.) 



The small tabular ducts, chiefly in the centre of 

 the lobules, cut obliquely and transversely. 



The ducts between the lobules ; in these the lumen 

 is large, and the epithelium consists of two or more 

 layers of cells. (These will not be seen in sections 

 from the outer part of the gland.) 



6. Under a high power, 



The alveoli vary in size; externally the basement 

 membrane shows as a rather sharp outline ; the lumina, 

 if visible, are small. In the round alveoli tubes cut 

 transversely where they do not branch it will be seen 



