350 



DUCTLESS GLANDS. 



ered probable that the suprarenal capsules are continually secreting 

 into the blood an active material, which although present in that 

 fluid only in minute quantities, may yet be sufficient to produce 

 very distinct effects upon the metabolic processes of muscular 

 tissue, and especially the muscular tissue of the vascular system. 

 It has, in fact, been stated by Cybulski, and this statement has 

 been confirmed by Langlois and by Biedl, that the blood of the 

 suprarenal vein contains a sufficient amount of the active principle 

 of suprarenal extract to produce a marked rise of blood-pressure 

 when intravenously injected. I have, in spite of careful experi- 

 ments, not been able to confirm this statement. Nor is it easy to 

 understand how it can be true, since such blood is constantly 

 flowing into the vena cava in larger quantity than these observers 



FIG. 191. Effect of suprarenal extract upon muscle-contraction in the frog : A, 

 normal muscle-curve of gastrocnemius ; B, curve taken during suprarenal poison- 

 ing, but otherwise under the same conditions as A ; time tracing ; 100 per second 

 (Schafer). 



injected. But whether we are able to show it experimentally or 

 not, there is very little doubt of the fact that the materials found 

 pass somehow or other into the blood ; and when we compare the 

 results of suprarenal injection with the effects obtained from the 

 removal and from disease of these organs, we can come to no 

 other conclusion than that we have before us a notable instance of 

 internal secretion ; and that the effect of such secretion passed 

 into the blood is beneficial to the muscular contraction and tone 

 of the cardiac and vascular walls, and even of the skeletal mus- 

 cles, appears very evident from the results both of the removal of 

 the organs and of injection of their extracts." 



Although in one case of Addison's disease in which fresh cap- 

 sules of the calf were administered there was apparent benefit, 

 the evidence is still too meager to draw any general conclusions as 

 to its usefulness in the treatment of this affection. 



