234 THE AMEIIICAN 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 flat in glycer- 

 ine. Make sections perpendicular to the surface after 

 hardening in gum and alcohol. Stain in hematoxylin, 

 mount in balsam. 



Lymphatics. — To inject the lymphatics of the rabbit, 

 begin l)y 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 tills the 

 lymphatics, is blackened and admirably marks out the 

 form and positio-n of the vessels. 



Blndothelium of the lym2)hatics. — 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 h 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 



