260 INTERNAL SECRETION 



The regulation and the maintenance of tone in every depart- 

 ment of the sympathetic system, is a function of the internal 

 secretion of the adrenal system. 



EXPERIMENTAL SUPRARENAL STIMULATION, 

 EXPERIMENTAL HYPERSECRETION. 



Although the symptoms of suppression which follow extirpa- 

 tion of the suprarenals have formed the subject of exhaustive study, 

 experiments in stimulation, by which the organs are impelled to 

 hyperactivity, are becoming increasingly rare. In the course of 

 his observations of the innervation of the intestinal movements, 

 Jacobj (1892) found that extirpation of the suprarenals was fol- 

 lowed, in fasting animals, by spontaneous intestinal movements; 

 and that epinephrectomy, similarly to resection of the splanchnic 

 nerve, negatives inhibition of intestinal movement without, how- 

 ever, producing paralysis of the vessels. These results induced 

 him to attempt experimental stimulation of the suprarenals. He 

 found that electric stimulation of these organs, as well as of the 

 nerves which connect the suprarenals with the ganglion coeliacum, 

 has the effect of arresting intestinal movements which are already 

 in progress. The secretion of urine is at the same time very much 

 diminished, and in two instances he found that suprarenal stimu- 

 lation was followed by an increase in arterial pressure. According 

 to Jacobj, the suprarenal nerves contain fibres which inhibit in- 

 testinal movement. These observations were not confirmed by 

 later authors (Pal, Apolant), but in the light of our present know- 

 ledge concerning the action of adrenalin upon blood-pressure, 

 peristalsis, and urinary secretion, they have a certain interest. 



In 1897, I investigated the physiology of the innervation of 

 the suprarenals, a subject which, up to then, had received no 

 attention. I found that the splanchnic nerve contains fibres which 

 cause vaso-dilation within the suprarenal area, and that stimula- 

 tion of these fibres produces suprarenal hyperaemia, the direct 

 result of the active vaso-dilation. That the suprarenals possess 

 also a vaso-constrictor innervation is to be inferred from the 

 effect which suprarenal extract has upon these organs, although 

 I was unable to trace the anatomical course of the vaso-constrictor 

 nerves. I also investigated the secretory process of the supra- 

 renals, together with the manner in which it might be modified 

 by the presence of secretory nerves. I made use of the vasotensor 

 action of the venous blood to determine the amount of active sub- 

 stance produced, but I was unable to obtain definite proof by this 

 method of the presence of suprarenal secretory nerves. The results 

 of my experiments, however, make it appear highly probable that 

 both the production of the secretion by, and its transference from, 

 the gland or, more correctly, the medullary portion of the gland 

 are subject to the control of the nervous system ; and that, more- 

 over, the splanchnic nerves contain suprarenal secretory, in addi- 



