The Effect of Nerves upon the Secretion 69 



adrenalin passed per minute was not increased. G. N. Stewart states that massage 

 of the suprarenals leads to the passage of an increased quantity of adrenalin into 

 the blood : when the massage is light a depressor effect is caused, when vigorous 

 a pressor effect ; but, according to Hoskins and M'Clure, there is never so large 

 a pressor effect as with "ordinary therapeutic dosage." 



Hoskins and Rowley find that administration of adrenalin does not increase the 

 excitability of the vasomotor nerves to faradisation, but rather tends to depress it. 



With regard to the amount of adrenalin required to produce a physiological 

 effect upon plain muscle, it may be mentioned that Cannon obtained inhibition 

 of a strip of intestinal muscle with a solution containing 1 in 20 millions, and 

 Janeway and Park observed inhibition of a strip of coronary artery of the sheep 

 with a solution of 1 in 50 millions. 



The Influence of Nerves upon the Secretion 



It was shown by Biedl that stimulation of the splanchnic nerves is 

 accompanied by increased blood-flow through the organ. The result is 

 even better marked when these nerves have been cut and allowed to de- 

 generate for two or three days so that only the vasodilators are acting. 

 Tscherboksaroff, in confirmation of an observation by Dreyer, found that 

 during excitation of the splanchnic in a dog the blood passing from the 

 suprarenal capsule by its vein produces a greater effect in raising the blood- 

 pressure of another dog than the blood of the suprarenal vein under ordinary 

 circumstances, and concluded that adrenalin is passed into the traversing 

 blood under the influence of impulses conveyed by this nerve. He also 

 obtained a larger amount of adrenalin from the suprarenal capsule as the 

 result of such stimulation. But the actual proof of secretion under the 

 influence of nerves is most satisfactorily furnished by the experiment of 

 Asher, who found that after ablation of the stomach, intestines, and all the 

 other abdominal organs, in order to eliminate the direct effect which would 

 be obtained on their blood-vessels, stimulation of the splanchnics still causes 

 a marked rise of blood-pressure, which fails if the suprarenal blood-vessels 

 are compressed. Elliott and Tuckett were able to exhaust the suprarenal 

 of its adrenalin by stimulation of its nerves. 



Section of the splanchnics diminishes the amount of adrenalin which 

 is passed into the blood : according to Elliott, it is only the reflex secretion 

 which is affected ; an automatic solution goes on all the time. Pende found 

 that section of the splanchnics leads eventually to atrophy of the medulla. 



Von Anrep noticed that stimulation of the splanchnic produces a double 

 rise of blood -pressure ; he ascribes the first to direct stimulation of the 

 vasomotors, the second to the outpouring of adrenalin into the blood. 

 This latter phase fails to appear if the suprarenals are extirpated (figs. 43, 

 44). In the cat Cannon found that the dilatation of the pupils and up- 

 standing of the fur which accompany sudden alarm or excitement are 

 associated with an increased outpouring of adrenalin into the suprarenal 

 veins, and he has drawn attention to the fact that many of the phenomena 



