EMERGENCY FUNCTION OF SUPRARENAL MEDULLA 175 



of sciatic stimulation. This vascular constriction appeared, however, 

 only when the suprarenal glands were connected with the circulation and 

 the splanchnic nerves were intact. When these glands were out of cir- 

 culation, asphyxia caused some rise of arterial pressure, though less than 

 in the intact animal, but no constriction of the vessels in the denervated 

 limb or kidney. He concluded, therefore, that the suprarenal glands arc 

 excited during asphyxia. These observations of Anrep on the constric- 

 tion of the vessels in the denervated limb were at once confirmed by Itami, 

 who found that it did not occur after transection of the cord. Since 

 the constriction was not due to the direct action of CO 2 on the vessel wall, 

 nor to reaction of the vessels to an increased internal pressure, he inter- 

 preted the result as due to increased suprarenal secretion. 



In 1914, Gasser and Meek, while making observations on a dog with 

 stellate ganglia removed and the vagi cut, noted, when the animal was 

 asphyxiated for 30 seconds, an acceleration of the heart amounting to 

 92 beats per minute. Now, under ether anesthesia, the blood vessels of 

 the suprarenal glands were tied. After recovery from the operation, 

 asphyxia lasting 90 seconds caused an acceleration of only 8 beats per 

 minute. 



In 1917, Gley and Quinquaud(c) found an amount of epinephrin in 

 suprarenal venous blood, obtained during asphyxia, considerably in excess 

 of that obtained when the animal was undisturbed. Using the rise of 

 blood pressure as a test, they determined that from 4 to 8 c.c. of the as- 

 phyxial suprarenal blood were equivalent to 16 c.c. of the blood before 

 asphyxiation. In their experiments injection of 20 c.c. of blood from 

 the inferior vena cava, taken above the suprarenal veins after 3 or 

 4 minutes of asphyxia, caused a rise of arterial pressure from 24 to 45 

 mm. higher than that produced by injecting an ecjual quantity of cava 

 blood taken from the same level before asphyxia. Asphyxiation of the 

 cat with the heart completely denervated caused, in Cannon's (e) experi- 

 ence (1919), a noteworthy increase in the heart rate, an effect which 

 was not seen after suprarenal extirpation. 



The foregoing evidence, which, like that obtained after sensory stimu- 

 lation, was the result of studies by various observers using a variety of 

 methods, is harmonious in leading to the conclusion that suprarenal secre- 

 tion is increased by the asphyxial state. 



Evidence that Suprarenal Secretion is Induced by Excitement. In 

 the experiments on the influence of emotional excitement, performed 

 by Cannon and de la Paz in 1911, the methods employed were similar to 

 those used by Cannon and Hoskins. The only differences were that the 

 animals did not receive a general anesthetic and that the catheter was 

 introduced under local anesthesia. Controls were obtained in every in- 

 stance. As the original records show, after emotional excitement the 

 blood drawn from the inferior vena cava anterior to the opening of the 



