HISTOLOGICAL DEMONSTRATIONS. 113 



(H.) Stratified squamous epithelium. The individual 

 cells and their nuclei may be clearly seen in the lower and 

 middle layers ; but near the free surface, where it is raised 

 into papillae, the scales are so compressed that in profile 

 they are not unlike fibres. The cells are jagged in the 

 deeper layers, but this appearance is not so well marked 

 here as in the skin. 



1 8 6. Examine (L.) V. S. human tongue, showing the 

 fungiform and filiform papillae ; a V. S. of the same, showing 

 a circumvallate papilla; a V. S. injected tongue, showing the 

 capillaries passing into the fibrous tissue at the base of each 

 papilla. 



187. Taste Bulbs. Examine (L. and H.) V. S. gustatory 

 disc of rabbit's tongue hardened in absolute alcohol. The 

 sections are stained with logwood, and mounted in glycerine 

 or dammar. The gustatory disc {papilla foliatd) is found 

 on either side of the dorsum of the tongue near its root 



Each taste bulb consists of a single layer of investing 

 ordinary epithelial cells surrounding a cluster of modified 

 epithelial cells, at the free end of which there is a short 

 and fine hair-like process, and at the other extremity delicate 

 protoplasmic processes that are probably connected with 

 nerve filaments. The bunch of hair-like processes projects 

 into an opening (gustatory pore} at the exposed extremity of 

 the taste bulb. In the human tongue the taste bulbs 

 chiefly occur on the outer aspect of the central projection 

 of the circumvallate papillae. 



Engelmann's article in Strieker's Histologv, vol. iii. p. I, may be 

 consulted by the advanced student for other methods of preparation. 



STOMACH. 



1 88. Methods. a. The stomach may be well hardened 

 in chromic acid and alcohol as described in 7. Sections 

 may be made in the freezing microtome, or by imbedding 

 in paraffin. The latter is, however, not nearly so good, for 

 the paraffin is very apt to enter the mouths of the glands. 

 The sections unstained are best mounted in Farrants' 

 solution or in glycerine. 



I 



