THE ADKENAL GLANDS 87 



in blood, and may give rise to a temporary glyeo- 

 suria (sugar in the urine) , which is a form of what 

 is commonly called "diabetes." It will be shown 

 that the pancreatic hormone acts antagonistically 

 to the adrenal hormone, thereby helping to regulate 

 body equilibrium. 



Professor Cannon has shown that an increase of 

 adrenaline in the blood occurs without any addition 

 of hormone from outside sources whenever an ani- 

 mal gets excited for example, when a cat gets 

 ready to defend itself against a dog's attack; and 

 also that such an increase is followed by a hyper- 

 glycemia (an increase of sugar in the blood) . This 

 suggestion that the adrenal gland is involved in 

 emotional outbursts is certainly of extraordinary 

 interest. The fact remains too that when a cat be- 

 comes frightened its "pupils dilate, the stomach and 

 intestines are inhibited, the heart beats rapidly, 

 the hairs of the back and tail stand erect all 

 signs of nervous discharges along the sympathetic 

 paths" ; and we have already seen how similar the 

 action of adrenaline and the stimulation of the 

 sympathetic fibers are. 1 



Summary. We may briefly summarize our 

 knowledge of the adrenals by stating that they are 

 unquestionably essential to life, though conflicting 

 theories are current as to their precise function. 

 Of the two parts into which the adrenals may be 



1 See further, Chapter XII. 



