172 W. B. CANNON 



In twg papers published in 1911, Cannon, in collaboration with de 

 la Paz and with Hoskins, brought forward evidence that the suprarenal 

 medulla was stimulated to secrete by emotional excitement, by "pain' 7 and 

 by asphyxia. In a series of papers which followed these first two, experi- 

 ments were described showing that suprarenal secretion was serviceable 

 in lessening muscular fatigue (Cannon and Nice; Gruber(d)) and in ac- 

 celerating coagulation of the blood (Cannon and Mendenhall). An inter- 

 pretative paper (Cannon (a), 1914) pointed out that excitement, pain and 

 asphyxia were conditions which in natural existence would commonly 

 be associated with struggle, and that the visceral changes, including supra- 

 renal secretion, which accompany these three states, would be useful in 

 great muscular effort. This interpretation presented a new view of the 

 function of the sympathetic division of the autonomic system and of the 

 suprarenal medulla in important bodily adjustments. 



Within the past few years both the evidence on which the foregoing 

 interpretation was based and the interpretation itself have been seriously 

 questioned. In an extensive series of papers, Stewart and Rogoff have 

 reported apparently careful quantitative studies on the rate of suprarenal 

 discharge, and have drawn the conclusions that the discharge is continuous, 

 that in any animal it is approximately constant, and that the supposed 

 variation is dependent on the rate at which the blood flows through the 

 lumbo-suprarenal veins (1917(/)). They found no increase of secretion in 

 pain (1917(t)), asphyxia (1917(<i)), or emotional excitement (1917(0)). 

 More recently Gley and Quinquaud(e) (1918) have also examined ex- 

 perimentally suprarenal secretion and have come to the decision that 

 epinephrin is not secreted in sufficient amount to be carried effectively to 

 the organs on which it may act, and that therefore no true physiological 

 "adrenalinemia" exists. There is then a sharp difference between the 

 views put forth by Cannon and his coworkers and the ideas supported by 

 these later investigators. In the following account the evidence for and 

 against special secretion will be presented and discussed. 



Review of the Positive Evidence 



Evidence That Suprarenal Secretion is Induced by Sensory Stimula- 

 tion. In the original tests Cannon and Hoskins made use of rhythmically 

 contracting segments of rabbit intestine suspended lengthwise in a glass 

 cylinder through which oxygen was passed. The segment, when not sur- 

 rounded by the blood to be tested, was bathed in Ringer's solution. The 

 test blood, the cylinder and the fresh Ringer's solution were all kept at 

 body temperature in a common bath. The blood to be tested was taken be- 

 fore and after the experimental procedures by passing a cathether through 

 a nick in the femoral vein into the iliac and thence into the inferior vena 



