SIGNIFICANCE OF THE SUPRARENAL GLANDS 131 



elaborating the method further for quantitative purposes Stewart (6) 

 (1912) and Stewart and Zucker(a, b) (1913) made it clear that no advan- 

 tage was to be gained from employing unclotted blood or plasma for the 

 tests on such objects as intestine or uterus instead of defibrinated blood or 

 serum, as claimed by O'Connor (a.) although they entirely confirmed his 

 finding, that for vascular test objects (frog perfusion preparation or artery 

 rings) it is essential to prevent clotting, on account of the vasoconstrictor 



Fig. 4. Intestine tracings forming a small sample of those used in the epinephrin 

 assay of a suprarenal blood specimen from a cat. At 37 and 39, Ringer's solution was 

 replaced by indifferent (jugular) blood diluted with an equal volume of Ringer's 

 solution. At 38 and 40 this was replaced by jugular blood made up with "adrenalin" 

 to a concentration of 1:2,000,000 and 1:3,400,000 respectively, the "adrenalin" blood 

 being diluted with an equal volume of Ringer's solution before application to the seg- 

 ment. At 41, Ringer's solution was replaced by jugular blood, and this at 42 by a 

 suprarenal blood specimen, both specimens being diluted with an equal volume of 

 Ringer's solution. The inhibition produced by 1:2,000,000 "adrenalin" is obviously 

 much greater than that produced by the suprarenal blood, which was assayed at 

 1:3,400,000. (Reduced to two-thirds.) (After Stewart and Rogoff, Am. J. Physiol.) 



substance set free from the platelets, as shown by Zucker and Stewart and 

 later by Janeway, Richardson and Park, who like H. A. Stewart and 

 Harvey (a) used and developed the artery ring method of Meyer. 



The quantitative relations of the epinephrin output of the supr arena Is 

 under definite experimental conditions were next investigated by Stewart 

 and Rogoff. In a series of papers they showed(6) (1916) that in all the 

 groups of animals studied (cat, dog, rabbit, and monkey), and in every 

 individual, a demonstrable amount of epinephrin is invariably present in 

 the blood of the suprarenal veins. If it occasionally seems to be absent, this 

 is simply because the test object is not sufficiently sensitive, as shown by 

 obtaining a positive result with a more sensitive object. They relied 

 mainly upon assays of the epinephrin concentration made in the drawn 



