202 THE AMERICAN MONTHLY [July, 



region, near the lower extremity of the oesophagus, 

 from the greater curvature and from the pylorus. 

 Spread out these, which should not be more than one 

 centimetre in diameter, and immerse in the fixing liquid 

 in a saucer or when attached to a cork. Strong alcohol, 

 osmic acid or the ammonia bichromate may be used ac- 

 cording to the special technique to be followed. Com- 

 plete the hardening, if necessary, in gum and alcohol. 

 Section, stain in picro-carmine, quinolein blue (after al- 

 cohol), Boehmer's hfematoxylin (after bichromate), and 

 alum carmine (after osmic acid). 



THE SMALL INTESTINE. 



This presents an epithelial lining, a glandular epith- 

 elium, a system of coats, vessels and nerves. 



Lining of epitheliuin. — Take a loop of the small intes- 

 tine of the frog or of the rabbit. Slit it open length- 

 wise and macerate it for 24 hours in the I alcohol. 

 With a scalpel scrape the inner surface and spread the 

 result on a slide in a drop of the alcohol. Stain in 

 picro-carmine, mount in glycerine slowly run under the 

 cover to displace the staining fluid. To prevent the 

 shrivelling of the cells by the glycerine, expose for ten 

 minutes to the vapor of osmic acid before staining and 

 mounting. If, after removing the cells in the J alcohol, 

 we add a very weak aqueous solution of aniline blue, we 

 can see the progress of the staining, the deeper layer of 

 cells taking the color, while the nucleus, the protoplasm 

 and the superficial layer are scarcely tinged. 



Glandidar epithelium. — The glandular element is re- 

 presented by Brunner's and by Lieberkuhn's glands. 

 The former are to be studied in the sections near the 

 pylorus. Fix by alcohol, stain with picro-carmine, sec- 

 tions cut by the gum and alcohol method. 



The glands of Lieberkuhn. — Dissociate the glandular 



