CHAPTER LXXXV 

 THE ADRENAL GLANDS (Cont'd) 



Variations in Physiological Activity 



Since it is clearly established that the adrenal glands are indispensable 

 to life and that extracts of them have a very pronounced physiological ac- 

 tion, it remains to consider whether the glands produce this internal secre- 

 tion within the body, and if so, whether it is essential for the well-being 

 of the animal or is required only under certain conditions. We must also 

 endeavor to find out upon which of the bodily functions of the intact 

 animal the internal secretion acts. These problems have been attacked 

 by three methods of investigation: (1) by comparing the epinephrine 

 content of similarly prepared extracts of the resting gland and of one 

 removed after a period of supposed increased activity; (2) by collecting 

 the blood as it flows into the vena cava from the adrenal vein and ex- 

 imining it for epinephrine by physiological tests. These consist in observ- 

 ing the behavior of some tissue that is sensitive to the action of epineph- 

 rine, such as the intestine or uterus, after applying the blood or serum 

 to it, or by injecting the blood or serum intravenously into another ani- 

 mal and looking for epinephrine effects; and (3) by allowing the blood 

 of the adrenal vein to be discharged under certain conditions through 

 the vena cava into the blood vessels of the same animal, and observing 

 the effect produced on certain physiological processes which in one way 

 >r another have been sensitized toward the influence of epinephrine. 

 s autoinjection method has recently been used successfully by Stew- 

 art and Rogoff, 19 their favorite structure upon which to observe the 

 epinephrine effect being the denervated pupil. 



Assaying the Epinephrine Content of the Gland 



With regard to the first mentioned of the methods, either chemical or 

 physiological means may be employed to assay the strength of the ex- 

 tracts. The best chemical method is that of Cannon, Folin and Denis, 10 

 the principle of which has already been described. The physiological 

 method yielding most satisfactory results is that of Elliott, 20 which con- 

 sists in injecting a portion of the extract intravenously into animals 

 from which the influence of the nerve centers on the heart and blood 

 vessels has been removed by decapitation. The rise in arterial blood 



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