THE ADRENAL GLAttDS 75 



The Glands of Combat, the glands of emergency energy, the 

 glands of preparedness, — such are the adrenal glands when 

 viewed from the adrenalin standpoint. A picture of its activity - 

 in the evolutionary scheme of struggle and survival is something 

 like the following: meeting an enemy, the animal is put in danger. 

 It must fight or flee for its life. In either case, certain conditions 

 must be fulfilled, if the body of the animal endangered is to be 

 saved. To prevent injury to itself, and to do as much injury as 

 possible to the foe — that becomes its immediate urge and neces- 

 sity. Of the two animals, if in one the heart should begin to 

 beat more strongly, the blood pressure to rise, the blood to flow 

 more rapidly through the attacking instruments, the muscles, 

 the teeth and claws, the brain and its eyes, while the other animal 

 experiences none of these, the former will be the victor in fight 

 or flight. Adrenalin may be looked upon as the invention for the •■-* 

 mobilization at a moment's notice, or as we say, after generations *. 

 of use, by instinct, of all these visceral and blood advantages 

 in the struggle of combat or flight. 



The nature of instinct, in its relation to the glands of internal 

 secretion, is a problem for another chapter. But we may note 

 that the James-Lange theory of an emotion regards it as a 

 consciousness of the very changes in the organism adrenalin 

 causes. Since adrenalin is the starter of the whole process, and 

 since McDougal has defined emotion as the feeling aspect of an 

 instinct, just as an instinct may be defined as the motor aspect 

 of an emotion, the adrenals as emotion-genetic, and instinct-gene- 

 tic, play a part in the most profound processes of the subcon- 

 scious and unconscious. 



The Mechanism of Fear 



We may therefore visualize a mechanism of fear. An instant 

 excess of adrenalin occurs in the blood of, say, a cat when it is 

 alarmed by the sight of a dog. In that cat, at the image of its 

 hereditary enemy, certain brain cells vibrate. A nerve tract, in 

 use as the line for that particular message in a hundred thousand 

 generations of cats, whirrs its yell to the medulla of the adrenal 

 gland. Through the tiny, solitary veins of the glands, an in- 

 finitesimal quantity of the reserve adrenalin responds. And with 

 what an effect! The blood, that primary medium of life, the 

 precious fluid that is everything, must all, or nearly all, be sent 

 to the firing line, the battle trenches, the brain and muscles, now 



