242 NUTRITIONAL PHYSIOLOGY 



The adrenal bodies are also numbered among the organs 

 which help to maintain the system in normal working order. 

 These are two inconspicuous structures placed one above 

 each kidney. Their microscopic features are obscure and 

 do not indicate a glandular organization. From the ad- 

 renal bodies can be obtained a powerful drug-like com- 

 pound, adrenalin, which the living cells of these organs may 

 be supposed to deliver continually to the passing blood. 

 Its presence in the circulation is evidently a necessity. 

 Destruction of the adrenals which sometimes results 

 from local tuberculosis produces the singular fatal dis- 

 turbance known as "Addison's bronze disease." An odd 

 feature of this condition is the dark pigmentation of the 

 skin, occurring sometimes uniformly and sometimes in 

 patches. More important, however, is the steady loss 

 of vigor affecting all the contractile tissues and leading to 

 death. 



Adrenalin injected into the blood-stream of an animal 

 shows its most marked effect in the intense contraction of 

 the small blood-vessels which is produced. This property 

 has made the substance valuable to surgeons, since it can 

 be used to check bleeding from cut surfaces. In like man- 

 ner it can reduce congestion in inflamed tissues, for example, 

 in a blood-shot eye. These artificial uses of adrenalin can 

 all be connected with its natural service, which is largely 

 in the direction of a reinforcement of contractility. Can- 

 non has recently called attention to this fact in an unex- 

 pected and interesting relation. 



He has proved by delicate tests that the blood of an 

 animal receives additional adrenalin during a terrifying 

 experience. For example, he has found the active com- 

 pound increased in the blood of a cat which has been kept 

 under restraint in the presence of a barking dog. There- 

 fore it must be concluded that one of the many bodily 

 accompaniments of an emotional outbreak is a stimulation 

 of the adrenal bodies to unusual activity. The value of 

 this reaction has just been made clear through the further 

 researches of the same investigator. It appears that 



