248 



PRACTICAL HISTOLOGY. 



[XXT. 



Epithelium. 



Crypt. 



Adenoid 

 tissue. 



Mucous 

 glands. 



Mucous 

 glands. 



are spherical masses of adenoid tissue, and into some crypts open the 

 ducts of small mucous glands (fig. 237). 



2. The mucous glands occur chiefly at the base of the tongue 



and along its edges. 

 They have the same 

 structure as the sali- 

 vary glands of the same 

 name (fig. 237), i.e., 

 their acini are lined by 

 a single layer of mucous 

 cell-s, but there are no 

 demilunes. They are 

 small compound tubu- 

 lar mucous glands. 



3. The serous glands 

 occur only near the 

 circumvallate papillae 

 and taste-bulbs. Their 

 acini are granular and 

 resemble those of the 

 parotid gland in struc- 

 ture (fig. 240, d). 



4. T.S. Tongue (Double-Stained). Stain a section from th<? 

 posterior part of the organ, first with methyl-green and then with 



cosin. Mount in balsam. The 

 connective tissue and papillae are 

 reddish ; the serous glands are red- 

 dish also, while the mucous glands 

 have a purplish-green colour. 



5. T.S. Injected Tongue (L). 

 This is obtained when the head or 

 whole body is injected. Observe 

 the very vascular muscular portion 

 and the papillae, each with an artery 

 entering it. If the papillae be com- 

 pound, i.e., beset with other smaller 

 secondary papillae, a small capillary 

 loop passes into each of these 

 secondary papillae ; sections of large 

 blood-vessels in the connective tissue 

 of the mucous coat (fig, 238). If 



FIG. 237. Crypt from Back of Tongue, with Cluster 

 of Lymphatic Follicles. 



FIG. 238. T.S. Injected Tongue of Cat. 



desired, another section may be faintly stained with logwood and 

 mounted as above. 



