THE SUPRARENAL SYSTEM 261 



tion to suprarenal vasodilator, fibres. My results have since been 

 confirmed by Dreyer, and completed by the successful demonstra- 

 tion of an increased vaso-constrictor action of the suprarenal blood 

 during stimulation of the splanchnic nerve. 



Erhmann was unable to discover, by means of the high'ly 

 sensitive frog's-eye test, that the adrenalin contents of the blood 

 in the suprarenal veins was changed by the addition of pilocarpin 

 or atropine. As we have already pointed out, Waterman and 

 Smit found an increase in the adrenalin contents of the blood in 

 the vena cava after faradic stimulation. These authors showed 

 at the same time that puncture of the floor of the fourth ventricle 

 produces, in addition to glycosuria, an increase in the adrenalin 

 production, the peripheral blood which is normally inactive 

 acquiring a mydriatic action after this operation. This finding 

 completes A. Mayer's discovery, already described, namely, that 

 after total epinephrectomy puncture of the fourth ventricle 

 ceases to produce glycosuria. 



These experiments prove beyond a doubt that the secretory 

 process of the adrenal system is under the control of the sym- 

 pathetic nervous system ; that the peripheral vasomotor and 

 secretory fibres are contained in the splanchnic nerve ; while 

 their centre is probably situated in the medulla oblongata. 



There have been, of course, numerous attempts to produce, 

 by experimental measures, alteration in the function of the supra- 

 renals and variation of their adrenalin contents. The results of 

 such experiments have already been described and, as we have 

 seen, a reduction in the adrenalin contents may be brought about 

 by the most varied methods, more particularly by the experimental 

 production of toxic and infective states. These findings are the 

 expression of hypof unction on the part of the organ. 



It is probable that hypersecretion on the part of the adrenal 

 system is illustrated by the results of an experiment made by 

 Battelli and Roatta. They found that, in the interval of repose 

 which followed exhaustive muscular exertion, there was an increase 

 in the adrenalin contents of the suprarenals of dogs. It is 

 probable that the changes in the suprarenal medulla and in the 

 extracapsular chromaffine substance observed by Schur and 

 Wiesel after renal injury, and regarded by them as- hypertrophic, 

 also belong in this category. 



An experimental hyperadrenalism is produced in animals 

 after each exhibition of adrenalin ; owing, however, to the 

 transient action of the substance the effect is very fleeting. By 

 means of Kretschmer's method of continuous transfusion of 

 minute quantities of adrenalin, a condition of hyperadrenalinaemin 

 may be maintained for several hours. The method seems likely 

 to throw still further light upon the results of this condition. 



The prolonged exhibition of adrenalin by subcutaneous, in- 

 traperitoneal, or intravenous injection does not, apparently, lead 

 to hyperadrenalinism. These methods serve, however, to illus- 



