416 



PHYSIOLOGY. 



in any organ. Its eft'ects on one organ are shown by contraction; 

 in another organ by inhibition. Thus, it causes contraction of the 

 spleen and inhibition of the movements of the stomach,, but in each 

 case it resembles the effect of stimulation of the sympathetic nerve 

 going to those organs. It is contraindicated in pulmonary hemor- 

 rhage. In default of sympathetic innervation, plain muscle is indif- 

 ferent to adrenalin. On irritation the splanchnics will not elevate the 

 blood-pressure after the removal of the adrenals. Extirpation of the 

 adrenals lowers the blood-pressure. Hence adrenalin excites the whole 

 sympathetic system. Ott first showed that adrenal extract arrests 

 peristalsis in diastole. This has been confirmed by several observers. 



Fig. 155. Effect of Suprarenal Extract upon Muscle-contraction in the 

 Frog. ( SCHAFEB. ) 



A, Normal muscle curve of gastrocnemius. B, Curve taken during supra- 

 renal poisoning, but otherwise under the same conditions as A; time trac- 

 ing; 100 per second. 



Blum has shown that adrenalin causes glycosuria by an action on the 

 glycogen of the liver. 



Oliver and Schafer found that when extracts of the suprarenals 

 were injected into the circulation very noticeable phenomena resulted. 

 Thus the arteries become greatly contracted, and the blood-pressure 

 rises very rapidly. This vasoconstrictor action is independent of the 

 main vasomotor center, which I have confirmed. Adrenalin dilates 

 coronary arteries. 



Adrenalin is a great muscle tonic, for it makes the cardiac con- 

 traction higher. It also slows the heart by a stimulation of the cen- 

 tral end of the vagus. It stimulates the unstriped muscle of the 

 arterioles through the myoneural substance, hence is a great vasocon- 



