746 THE ENDOCRINE ORGANS, OR DUCTLESS GLANDS 



hypersecretion of epinephrine into the blood. The results seemed to con- 

 firm the hypothesis. In the first place, it was found that, whereas the blood 

 drawn from the vena cava opposite the entry of the adrenal veins (by 

 passing a catheter up the femoral vein till its free end lay at this level) in 

 a normal male cat did not give evidence of the presence of epinephrine 

 when tested by means of the intestinal segment method, it did so in a 

 cat that had previously been frightened by allowing a dog to bark at it, 

 Such results were not obtained after removal of the adrenal gland, or in 

 a female cat, which is usually indifferent to such a method of frightening. 

 Cannon also thought that many of the other adaptations which take place 

 in an animal in this condition are in part dependent on the presence of an 

 excess of epinephrine in the blood. The three most important of these 

 are: (1) increased discharge of sugar from the liver into the blood; (2) in- 

 creased efficiency of muscular contraction; (3) diminished clotting time of 

 the blood all of which are adaptations enabling the animal either to con- 

 quer the source of the fear or to be in a better position to recover from 

 any bodily injury involving a loss of blood should he suffer bodily dam- 

 age. Stewart and Rogoff have more recently thrown considerable doubt 

 on these conclusions by finding that cats in which both adrenal glands are 

 entirely removed from the influence of the nervous system, behave like 

 normal animals when frightened, and develop hyperglycemia when as- 

 phyxiated or etherized. It is scarcely necessary to point out that, until 

 it is definitely established by experimental investigation that epinephrine 

 may be discharged in excessive amounts under certain conditions, it is 

 irrational to assume that such may occur in disease. The surgical removal 

 of the adrenal gland is certainly not warranted under any circumstances, 



The Association of the 1 Adrenal with Other Endocrine Organs 



We have at present very little accurate and reliable information on the 

 association of the adrenal with other endocrine organs. That epinephrine 

 has an influence on many diverse organs and glands is an undoubted 

 fact, but this is more probably to be attributed to an activating influence 

 on sympathetic nerve endings than to any specific relationship between 

 the adrenal glands and the gland in question. The most important of the 

 results that have been obtained are the following: 



1. With the Thyroid and Parathyroid. Cannon alid Cattell, after con- 

 firming Bradford's discovery that an electric current of action is set up in 

 the salivary gland when it is excited to activity, proceeded to investigate 

 the occurrence of such a current in the thyroid gland. 73 By placing one 

 nonpolarizable electrode on the gland itself and the other on the neigh- 

 boring subcutaneous tissues or on the trachea, a current was found to be 

 set up by stimulation of the sympathetic nerve supply of the thyroid, by. 

 intravenous injection of epinephrine, or by stimulation of the great 



