234 THE AMERICAN MONTHLY [Aug, 



When the material returns through the vena cava, close 

 the latter and till the vessels. About fifteen cc. will be 

 needed for a small rat. When cold, open the abdomen 

 and place it in 2 per cent bichromate. With the scissors 

 remove pieces bearing villi and examine fiat in glycer- 

 ine. Make sections perpendicular to the surface after 

 hardening in gum and alcohol. Stain in hsematoxylin, 

 mount in balsam. 



Ly/uphatics. — To inject the lymphatics of the rabbit, 

 begin by injecting the blood vessels with the red or 

 carmine mass. Thrust a short hypodermic needle into 

 the mesentery near its attachment to the intestine and 

 force in the Prussian blue mass. Spread out the intes- 

 tine in a saucer of alcohol ; cut sections perpendicular 

 to the surface ; mount in balsam. 



Physiological iiijection of the lymphatics. — Starve a rat 

 for twenty-four hours, then feed it on fat. Cut out, 

 with scissors, some villi, and expose to , osmic acid 

 fumes. Mount in glycerine. The fat, which fills the 

 lymphatics, is blackened and admirably marks out the 

 form and position of the vessels. 



Eiidotheliu7n of the lymphatics. — Proceed as for the 

 injection of the lymphatic vessels of the rabbit, using 

 the following silver nitrate injecting mass : Grelatine, 

 2 ; one per cent solution silver nitrate, 1. Soak the 

 gelatine in distilled water, melt it on a water bath and 

 add the silver solution. 



(1) Cut sections perpendicular to the surface of the 

 intestine after hardening by gum and alcohol. 



(2) Put a portion in the I alcohol for 24 hours, brush 

 away the epithelium, remove the muscular layer and ex- 

 amine the mucous membrane mounted flat in balsam. 



Nerves of the small intestine. — We select a loop of 

 the rabbit's small intestine in which to study the plexus 

 of Meissner and that of Auerbach. Ligate the intestine 



