166 GLANDS IN HEALTH AND DISEASE 



lation, and that the only way in which the experi- 

 ment would indicate an increased concentration of 

 adrenaline in the blood is if the blood flow through 

 the adrenal vessels were retarded. 



The denervated heart as an indicator of adrenal 

 secretion. In this method instead of removing 

 blood from the body, the denervated heart is used 

 to demonstrate an increase of adrenaline in the 

 blood. "In a cat under urethane, with vagi (nerves 

 of sensation and motion) cut and stellate ganglia 

 (referring to nervous matter) excised, stimulation 

 of the central end of the cut sciatic will cause the 

 heart rate to increase in some instances as much as 

 50 beats per minute. . . . The completely dener- 

 vated heart can be used as an indicator of adrenal 

 secretion in testing the influence of emotional ex- 

 citement quite as well as in testing the influence of 

 sensory stimulation and asphyxia. 1 The results 

 obtained with the isolated heart used as an indi- 

 cator of adrenal secretion thus confirm in every 



1 Again for the benefit of some readers certain details should 

 be added. To denervate the heart the stellate ganglia are first 

 removed under ether with aseptic precautions; later the right 

 vagus nerve is severed below the recurrent laryngeal branch; and 

 still later the left vagus nerve is cut in the neck. The heart is 

 thus wholly disconnected from the central nervous system, and 

 any agency causing an increase in the heart rate must exert its 

 influence through the blood stream. With the adrenal glands 

 normally innervated the rate was 217 per minute when the animal 

 was calm, and 255 when excited. After the adrenal glands were 

 removed the rate when calm was 217 and when excited 221, an 

 inappreciable difference. 



