72 LABORATORY MANUAL OF GENERAL PHYSIOLOGY 



above level of frog. Bottle B, about 12 cm. above level of frog, contains 

 about 0.0005% phenol red in oxygenated Ringer. In Hober's perfusion 

 method a dye dissolved in Ringer solution is introduced into the frog's 

 kidney from the renal portal vein while the renal artery is supplied by 

 Ringer. (See Fig. 7.) 



Pith brain and spinal cord of male frog. Tie string tightly about each 

 leg, where it joins the body. Make incision on each side, carefully, 



liver he.art j (f 



mesenteric 

 artery. 



obdominol vein- 



Fig. 7. — Diagram of circulation in frog's kidney with position of cannulae for perfusion (not 

 drawn to scale). Sketch by Vance Tartar. 



from lower part of abdomen to point ^ in, above pectoral girdle. In 

 doing this, cut through pectoral girdle with heavy scissors. The incision 

 should be through the skin and muscles of the body wall. Join the two 

 incisions by a cut across the base of the mouth. 



Carefully lay back strip so delineated, cutting muscles as you do so. 

 Stop before severing the vena abdominalis. This vein clings to the inner 

 side of the strip and leads into the heart. Ligate the vein with thread, 

 then sever from heart. 



Remove the liver. Donot hesitate to sever the hepatic veins. Dissect 

 out the intestinal tract. Be sure not to injure the spleen or the splenic 

 artery, which runs to the abdominal aorta. Separate these from the rest 



