SIGNIFICANCE OF THE SUPRARENAL GLANDS 155 



evidence, see preceding chapter.) Stewart and Rogoff have often observed 

 a slight fall of pressure when the cava pocket is closed off so as to exclude 

 the suprarenal blood from the circulation. But any direct share which 

 the epinephrin may take in maintaining the normal blood-pressure must 

 be insignificant, and even when the rate of output is much increased by 

 stimulation of the nervous mechanism, e.g., by strychnin, no effect at all 

 comparable in magnitude with the effects ordinarily produced by the 

 vasomotor mechanism can be elicited. This is true even when the supra- 

 renal blood is collected for some minutes and then released. In the 

 present position of our knowledge any claim that the epinephrin liberated 

 from the suprarenals exerts or can exert an obvious, striking and easily 

 demonstrated action upon any function of the body must be considered 

 almost as suspect. It is essential that the quantitative aspect of the 

 epinephrin output be kept steadily in mind in considering this question. 

 For if enough epinephrin be injected into an animal reactions of great 

 magnitude can, of course, be elicited. 



Quite recently Gley and Quinquaud(/) (1919) have again demonstrated 

 that epinephrin does not directly play a part in maintaining the arterial 

 pressure, since ofter removal of the suprarenals the pressure does not fall, 

 at least during several hours. They have repeated the experiments of 

 Strehl and Weiss, mentioned earlier in the article, which have often been 

 quoted as proving a marked fall of blood-pressure on occlusion of the 

 left suprarenal vein (after previous removal of the right gland). These 

 experiments are a good illustration of the fact that considering the mag- 

 nitude of the epinephrin output any large effect alleged to be due to its 

 suppression or increase is suspicious. The French authors show con- 

 clusively that practically no change of pressure occurs, and trace the results 

 of Strehl and Weiss to technical errors. There is no evidence that in 

 conditions associated with a low blood pressure (shock) there is any 

 attempt at compensation by an increase in the epinephrin output (Hender- 

 son, Prince and Haggard; Stewart and Rogoff(r), 1919; Bedford, 1917). 

 (Fig. 23). 



Although no immediate effect on the blood-pressure may be shown 

 on suppressing the epinephrin output, it has been supposed that epinephrin 

 may exert a function in activating or increasing the irritability of the 

 sympathetic system including the vaso-constrictor and cardio-augmentor 

 fibers or of the f intermediate link (myoneural junction) between them and 

 the muscular fibers (Elliott(&) 1905). Gautrelet and Thomas (ft) stated, 

 in support of this hypothesis, that after removal of both suprarenals there 

 is a diminution of the direct and reflex excitability of the sympathetic 

 nervous system. They noted a remarkable alteration in tne psychical con- 

 dition : rats which before the operation were wild and attempted to bite 

 were quite tame and subdued after it. This is quoted here because there 

 is a tendency in much of the literature to emphasize a supposed role of 



