210 R. G. HOSKINS 



changes in the general circulation and reactions in the portal circulation, 

 Burton-Opitft was led to subscribe to the opinion that the portal vein is 

 supplied with venomotor fibers. 



Both Schmid and Burton-Opitz noted that there is a marked difference 

 in reaction in different animals of the same species, some showing an in- 

 creased and others a decreased inflow. The apparent explanation was 

 offered that in some cases the liver vessels receive but little of the in- 

 jected epinephrin as compared with other abdominal vessels, while in 

 other cases a proportionately larger amount of the drug enters the portal 

 circulation. 



Edmunds (1915) subjected the problem to renewed study, making 

 both plethysmographic and perfusion experiments. His work was done 

 mainly upon dogs, though a few experiments upon cats also were 

 reported. Blood-pressure from the carotid artery was recorded during 

 the course of the plethysmographic studies. The epinephrin was injected 

 into the femoral vein. "Small" doses (0.5 to 1 c.c. of 1 :25,000 or 1 :50,000 

 solution) were employed. A special type of plethysmograph was devised 

 and adapted to the left lobe of the liver. 



Edmunds' observations with the plethysmograph confirmed those of 

 previous observers with the Stromuhr, in showing distinct differences in 

 the manner of reaction to epinephrin by different dogs. The plethysmo- 

 graph was found to have the advantage of showing definite circulatory 

 changes of such brief duration as to escape detection by the Stromuhr. 



Most commonly it was found that immediately after the blood-pressure 

 began to rise the volume of the liver decreased and the contraction lasted 

 throughout the period of the systemic reaction. The liver volume then 

 gradually returned to normal, in this phase apparently passively follow- 

 ing the blood-pressure. The vasomotor effect in the liver obviously per- 

 sisted longer than in other parts of the body. An interesting variant of 

 this reaction was seen in some dogs and proved to be the characteristic 

 reaction in cats. In such animals no decrease whatever in liver volume 

 was seen, but an increase which outlasted the rise in systemic blood pres- 

 sure. Associated with this was an increase in the amplitude of contrac- 

 tion of the right ventricle. Edmunds accordingly interpreted the dilata- 

 tion in the liver as due to a cardiac factor. In view of the active vasodila- 

 tation which has been demonstrated in other organs as a reaction to epi- 

 nephrin, it would seem that the phenomenon is worthy of further study. 



Edmunds attempted to simplify the problem by controlling the hepatic 

 circulation while registering liver volume. Normal tracings were first 

 taken and then the hepatic artery -occluded and the tracing repeated. The 

 result of clamping this artery was to bring all the various types of reac- 

 tions and curves into a single group. The reaction now consisted of two 

 phases. During the first twenty to thirty seconds following the injection 

 of epinephrin there was either no increase in volume or a very gradual 



