SIGNIFICANCE OF THE SUPRARENAL GLANDS 151 



hard to understand how this could explain the difference in result, since 

 Dale and Laidlaw observed that section of the splanchnics after the injec- 

 tion of pilocarpin did not interfere with the augmented secretion of epi- 

 nephrin, and Stewart and Rogoff(^) did not cut the splanchnics. 



According to Tscheboksaroff (a) physostigmin increases the epinephrin 

 output. This was confirmed by Stewart and ~Rogofi(w) who observed an 

 increase (to 10 times the initial output). The action is a central one. 

 Strophanthin has no clearly demonstrable or constant effect (Stewart and 

 Rogoff(p) 1919), although some increase was deduced by Richards and 

 Wood (a) (1914-15) from observations made by the catheter method on 

 vena cava blood. 



Functions of Epinephrin in the Body 



The facts that a measurable amount of epinephrin is constantly passing 

 into the blood stream, that this amount reckoned in proportion to the 

 body weight varies but little in different animals and under a variety of 

 experimental conditions, and that the epinephrin output is completely 

 under the control of the nervous system strongly suggest that it must 

 exercise some function in the body. It is true that the epinephrin, which 

 in the blood plasma of the suprarenal veins rarely attains a concentration 

 exceeding 1 :500,000 and with ordinary blood flows is usually only a fifth 

 of this or less, is diluted probably 100 to 200 times at least before reach- 

 ing the lungs. Even if no loss of epinephrin is suffered in the pulmonary 

 circulation, as is probable from Elliott's (b) experiments (1904), the plas- 

 ma can hardly reach the systemic arteries under ordinary conditions with a 

 greater concentration of epinephrin than 1 :250,000,000 to 1 :500,000,000, 

 corresponding to 1:400,000,000 or 1:500,000,000 to 1:1,000,000,000 for 

 the blood. This agrees fairly well with the approximate estimate of 

 Trendelenburg(e) (1915) of the vasoconstricting power of freshly drawn 

 citrated blood from the rabbit's carotid when tested on the frog perfusion 

 preparation. Although this method is exceedingly sensitive there is al- 

 ways the possibility that some part of the constrictor effect may be due to 

 the vasoconstrictor substance developed from the platelets. But in these 

 careful experiments Trendelenburg seems to have controlled this factor 

 as well as is possible. He considers, however, that the true epinephrin 

 content of the arterial blood may be even less than 1:1,000,000,000. In 

 passing through the capillaries practically all the epinephrin disappears 

 even when by continuous infusion of epinephrin into the arteries the 

 concentration in the arterial blood is raised to a value much above the nor- 

 mal. All the statements in the literature purporting to show measurable 

 contents of epinephrin in the peripheral venous blood are erroneous, and 

 are based upon faulty methods. For example Frankel professed to find 

 by the rabbit's uterus segment method a definite content of epinephrin in 

 normal human serum, which was increased in Graves' disease but not 



