94 MEDULLA 



omy, pain, or even fastening the animal. In order to do this, 

 these authors in a preliminary operation cut the dorsal roots 

 from the ninth thoracic to the third lumbar vertebra, thereby 

 rendering the area in the vicinity of the adrenals anesthetic to 

 manipulation. After about one month when the animal had 

 recovered from this preliminary operation, an incision was 

 made below the costal margin and the adrenal vein cannulated. 

 As pointed out by Satake" and his collaborators, their method 

 obviously will interfere with the normal blood flow of the 

 adrenal. Despite this objection their experiments offer a 

 decided improvement on those of their predecessors and the 

 results obtained are undoubtedly of greater physiological 

 significance. To avoid the interference with the normal blood 

 flow occasioned by introducing the cannula into the adrenal 

 vein, it would be of interest to repeat the experiments utilizing 

 the thermostromuhr method for determining the blood flow. 

 Measuring the rate of blood flow by this procedure and remov- 

 ing samples of blood for analysis with a syringe and fine 

 needle inserted into the exposed adrenal vein, would enable 

 one to obtain results which more closely represent normal 

 physiological conditions. The average blood flow through 

 each adrenal observed by Satake et alii was 0.3 cc. per kilo 

 per minute. The authors used the rabbit's intestine for the 

 assay of epinephrine. 



12. Eider's method. Euler 188 has utilized a method for 

 determining the epinephrine content of blood serum based on 

 the activating action of this substance on the reduction of 

 methylene blue added to muscle extract. Although, as Euler 

 showed, such activation by blood serum is not entirely due to 

 epinephrine, the method has been found useful under various 

 conditions. 



THE NORMAL RATE OF EPINEPHRINE SECRETION 



Considerable work has been done to determine the rate at 

 which epinephrine is normally secreted from the adrenal glands. 



