86 



Scientific Proceedings (73). 



tion of Hoskins's method was used. The essential part of the 

 method is that the tone of rabbit intestine, immersed in oxy- 

 genated blood at 37 degrees C, is lowered and the rhythmic 

 contractions more or less inhibited by the presence of epinephrin 

 in the blood. 



To determine the quantitative relation of epinephrin in the 

 samples of blood tested, two methods were used. In one method, 

 the tracings obtained were compared with tracings obtained on 

 the addition of known amounts of adrenalin to control blood. 

 In the second method, the blood giving the reaction for epinephrin 

 was diluted with control blood until the reaction of this blood 

 was similar to that of the compared blood. 



Low blood pressures were brought about by one of there 

 methods; 



1. Handling of intestines. 



2. Hemorrhage. 



3. Occlusion of the thoracic inferior vena cava. 



In most of the experiments, pressures of 30 to 40 mm. of mercury 

 were obtained. 



In all three types of experiments, the epinephric content of 

 the adrenal blood was increased, provided that the pressure was 

 sufficiently low and the condition of low pressure was maintained 

 for a sufficient length of time. Since the blood was diluted with 

 control blood to compensate for the difference in the rate of flow 

 through the adrenal organ, an increased activity of these organs 

 was indicated. 



In some cases, it was necessary to dilute the experimental 

 adrenal blood with thirty- two times its volume of jugular blood, 

 before a tracing could be obtained similar to that of adrenal 

 blood, drawn before low pressure was induced. In other cases 

 the reaction was similar to the reaction given by control blood 

 to which had been added adrenalin sufficient to make a 1 to 

 10,000,000 dilution. 



In experiments in which samples were taken at intervals, it 

 was shown that the marked increase of epinephric content of 

 blood occurred only after a considerable duration of a condition 

 of low blood pressure, varying from one to two hours. 



In these experiments, the later samples indicated an increasing 

 amount of epinephrin in the blood. 



