140 



PRACTICAL HISTOLOGY. 



[VI- 



ADDITIONAL EXERCISES. 



11. Cover-Glass Preparation of Goblet-Cells. Place the oesophagus or 

 stomach of a frog in dilute alcohol for twenty-four hours. Scrape the mucous 

 surface and compress the scrapings between two cover-glasses. Separate the 

 cover-glasses, allow the film adhering to each glass to dry, and then stain 

 it with eosin or aniline-water-methyl-violet, or safraniii-0. Wash off the 

 surplus stain with absolute alcohol, allow the film to dry, and mount it in 

 xylol-balsam. 



Perhaps a better plan still is to stain the cover-glass preparations for 

 twenty-four hours in Ehrlich-Biondi fluid. It is prepared thus : 



Ehrlich-L'iondi Fluid. 



Saturated watery solution of orange . 



,, acidfuchsin . 



,, ,, methyl-green . 



100 cc. 

 20,, 



50 



The solutions used, however, must be saturated. When used as a staining 

 agent, this strong fluid is diluted with about forty volumes of water. 



(a.) Observe the goblet-cells with their characters retained intact. In the 

 Ehrlich-Biondi preparation the protoplasm is stained red, the nuclei and 

 nucleoli bluish. 



12. Cover-Glass Preparation of Ciliated Epithelium. The mucous mem- 

 brane of the oesophagus of a frog is placed for twenty-four hours in dilute 

 alcohol. A cover-glass preparation is made of the epithelium, and stained as 

 described under 11, with methylene-blue, safranin-0, gentian-violet, or 

 Ehrlich-Biondi fluid, and mounted in xylol-balsam. 



13. T.S. Tongue of Frog (H). By means of hedgehog-spines, pin out the 

 tongue of a frog on a thin layer of cork with a small hole in it. Harden it for 

 two hours in a saturated watery solution of corrosive sublimate ; remove every 

 trace of the sublimate by prolonged washing in alcohol not water. Stain in 



bulk in picro-carmine or borax-carmine. 

 Make transverse sections best by the 

 paraffin infiltration embedding method 

 (p. 41) and mount the sections in 

 balsam. 



(a.) Observe the fibro-muscular basis of 



the tongue ' covered on the surface with 



ciliated epithelium cells; between the 

 ciliated cells the goblet-cells, each with an 

 open mouth and its plexus of fibrils with 

 muoigen in its meshes (fig. 104). 



(b.) Observe, too, how the expanded 

 ovoid goblet-cells compress the ciliated 



FIG. ,04-V.S. Ciliated Epithelium of C , ells *1 cause the latter to have a peculiar 

 Frog's Tongue. TO. Muscular fibres, shape, a broad expanded top and a narrow 

 Corrosive sublimate and picro-car- body. 

 carmine, x 250. ( r . ) The young cells at the base of the 



ciliated cells. 



If the specimen be stained in picro-carmine and mounted in balsam, the 

 yellow colour of the picric acid can be retained by putting a little picric acid 

 into the alcohol used to dehydrate it, or by picric acid placed in the clove-oil 

 or xylol used to clear up the section. 



