56 



STUDENTS HISTOLOGY 



size of the drop of saliva should be carefully adjusted so as to fill 

 the space between the cover- glass and slide. Too little will cause 

 the cover to adhere so tightly to the slide as to press the cells out 

 of form; too much, and the saliva flows over the cover and soils 

 the objective. With a glass rod place a drop of the dilute eosin 

 solution on the slide, and with a needle lead it to the edge of the 

 saliva. The dye will pass under the cover slowly, and whatever 

 anatomical elements there may be present will be gradually stained. 

 Observe that the nuclei of the flat scales first take the dye and 

 appear of a deep pink; while the other portions are either colorless 

 or very lightly stained. 



Find a typical field and sketch it with a pencil, afterward tint- 

 ing with dilute eosin. 



An admirable view of the surface of a squamous epithelium may 

 be had by using the superficial layer of the skin of a frog, which is 



FIG. 30. SQUAMOUS EPITHELIAL, CELLS FROM THE MOUTH. 



often shed when the animal is kept in confinement. It may be 

 stained with haematoxylin; and small pieces, after alcohol and 

 clearing, may be mounted in balsam. 



PAVEMENT EPITHELIUM 



When thin, flat cells are disposed in a single layer, like tiles, 

 the epithelium is termed simple squamous, pavement, or tessellated. 

 These cells are often quite regularly polygonal (although this 



