EMERGENCY FUNCTION OF SUPRARENAL MEDULLA 183 



conclude, therefore, that the epinephrin present in suprarenal blood after 

 splanchnic stimulation is found neither in the blood of the vena cava 

 above the sjibhepatic veins nor in the blood of the heart. 



In drawing this conclusion Gley and Quinquaud seem to have disre- 

 garded the fact that they were, in the first place, taking only a small 

 portion of the secreted epinephrin, which had already been diluted by 

 the blood of the donor, and were then injecting this small portion into 

 the blood stream of another dog, where it would be diluted to a much 

 greater degree. 



Gley and Quinquaud declare categorically that secreted epinephrin 

 is not carried by the circulation to the organs on which it acts, and that, 

 if present at all, it is present in a quantity altogether minimal and insuffi- 

 cient to exercise its action. This declaration again is made without due 

 regard to evidence already in the literature. The observations on the 

 denervated limb, on the denervated kidney, on the denervated salivary 

 gland and on the denervated heart, quoted or described above, present 

 evidence that suprarenal secretion may be stimulated by painful im- 

 pulses, by asphyxia and by emotional excitement, and that the substance 

 secreted under these circumstances not only is carried to the structures 

 on which it acts, but produces on these structures pronounced physiological 

 effects. Until this evidence is definitely proved to be unworthy of accept- 

 ance, the conclusion which Gley and Quinquaud have drawn must be 

 regarded as unjustified. 



Interpretation of the Function of the 

 Suprarenal Medulla 



With the fading out of the view that the suprarenal glands pro- 

 duce some substance which neutralizes toxic material developed in the 

 body, there have been left two main theories to account for the role played 

 by the suprarenal medulla in the bodily economy. These are the tonus 

 theory and the emergency theory. 



The tonus theory, which has been advocated in the past (Elliott, 1904, 

 1914(/) ; Biedl, 1913 (/)) and still receives attention, holds that the func- 

 tion of the secreted epinephrin is to maintain the sympathetic endings in a 

 state of responsiveness to nervous stimulation or in a condition of moderate 

 activity or tone. This view has definitely lost ground in the course of rela- 

 tively recent researches. A number of investigators have called attention 

 to the depressive effect of small doses of epinephrin (Hoskins and Mc- 

 Clure(fe), Cannon and Lyman). If the smallest dose which will have any 

 influence whatever on the blood vessels induces relaxation of the vessels, 

 it is difficult to understand how the function of the secreted epinephrin 

 could be that of maintaining a state of tonic contraction. Furthermore, 



