EFFECTS OF SECRETION ON THE HEART AND VESSELS. 13 



established a cycle of afferent and efferent impulses of which 

 the medulla and the portion of the cord immediately below it 

 represent the center. The effects of destruction of these 

 structures can easily be foretold. As shown by Strieker nearly 

 thirty years ago and by other physiologists since, extirpation 

 of the cervical and dorsal portions of the cord causes arrest 

 of the heart's action. When to this is added destruction of 

 the medulla, the certainty of immediate death is but enhanced. 

 Again, certain agents chloral hydrate, for instance are 

 known to abolish the functional activity of the cord and to 

 affect the heart as if the vagus had been severed. 



Applying these classical data to the question in point, it 

 becomes evident that, if the inhibitor or augmentor centers 

 were directly or reflexly stimulated by suprarenal extract, the 

 effects of extirpation of these centers or of the cord would 

 not be counteracted by its use since there would be no center to 

 receive and transmit impulses. The arrest of the heart's action 

 would therefore be permanent. 



But experiments have shown that the injection of supra- 

 renal extract at once causes this organ to resume its beats not- 

 withstanding total extirpation of the entire cord. Thus, Biedl 44 

 cut the medulla oblongata and removed the entire cord of 

 mammals; and, when the blood-pressure had become reduced 

 to 9 millimeters, injected suprarenal extract. This at once 

 brought up the pressure to 160 millimeters. Gottlieb 45 chlo- 

 ralized rabbits until the heart-beats became irregular and ex- 

 cessively slow. An injection of suprarenal extract at once 

 restored the regularity and volume of the pulse. He tried 

 the same experiment when the pulse was no longer registrable 

 by the manometer; a similar result was obtained, and the heart 

 almost immediately resumed its normal action. Isaac Ott 46 

 etherized a rabbit, cut the cord above the atlas, severed all 

 the cardiac nerves in the neck, and verified the section of the 

 cord post-mortem. Injections of suprarenal extract were then 

 used repeatedly as soon as the pressure became greatly lowered. 

 They brought it up from 24 to 144 the first time, from 17 to 



"Biedl: Wiener klin. Wochenschrift, Bd. ix, 1896. 



48 Gottlieb: Archiv fur exp. Path, und Phar., Bd. xxxviii, 



46 Isaac Ott: Experiment No. 11, Medical Bulletin, Jan., II 



