208 PRACTICAL HISTOLOGY, 



acid and logwood may also be employed in the same 

 way as with the sections of skin (p. 186). The strati- 

 fied epithelium, the papillae of the mucous membrane, 

 and the arrangement of the muscular fibres as well 

 as the mode of termination of the superficial mus- 

 cular fibres in the connective tissue of the mucous 

 membrane, may be studied in these sections. Some 

 of the sections include mucous glands, which differ 

 in appearance according to their condition at the 

 time of death. If they had not been recently stimu- 

 lated by the ingestion of food or otherwise, the cells 

 of the gland will still be filled with mucus, as shown 

 by their swollen appearance, and by their becoming 

 strongly stained by the logwood; whereas, on the 

 contrary, if they have recently discharged their 

 secretion, the cells will be granular and almost color- 

 less, and there will be indications of mucus in the 

 lumina of the ducts. 



Besides the mucous glands others may be seen in 

 the neighborhood of the papillae vallatas, which 

 secrete no mucus, and consequently do not present 

 the above differences of staining. Their ducts, if 

 the section pass in the direction they take, will be 

 found to open almost without exception into the 

 fossae of the circum vail ate papillae, or, at all events, 

 near those parts in which taste-buds have been 

 found. The taste-buds themselves may possibly be 

 seen in the epithelium on the sides of the papillae 

 vallatae, and also in that which covers the mucous 

 membrane- near the root of the tongue on each side. 

 The description of other modes of preparing them 

 will, however, be deferred until the organs of special 

 sense are treated of. 



Preparation 8. Vessels of the tongue. Sec- 

 tions should also be made of an injected tongue. 

 These will show not only the numerous vascular 

 loops in the more obvious papillae of the mucous 

 membrane, corresponding in number with the micro- 

 scopic secondary papillae, but also the arrangement 

 of the vessels in the muscular substance of the organ. 



