134 G. K STEWART 



would be about 0.00018 mgm. Popielski's(a) result of 0.004 mgm, per 

 kgm. per minute for the dog is probably 20 times too great, It is worthless 

 because of the method employed (compression of the aorta for a given 

 time and imitation of the rise of pressure produced on release by in- 

 jection of "adrenalin"). He is perfectly correct,, however, in stating that 

 a demonstrable effect on the blood-pressure after release of the aorta can 

 sometimes be obtained. This is due to the release of blood from the supra- 

 renals containing epinephrin, secretion of which has been going on steadily 

 during the period of occlusion. 



In two macaque monkeys examined by Stewart and Rogoff(e) (1919) 

 the output per kgm. per minute was respectively 0.0002 mgm. and 0.00015 

 mgm. 



It is obvious that a surprisingly close agreement exists in the results 

 of those observers who have estimated the epinephrin output in drawn 

 suprarenal vein blood on suitable test objects by adequate methods. This 

 is true not only of one group of animals, but of all the mammals care- 

 fully examined. The presumption is strong that the output observed 

 is not an artificial phenomenon varying widely with the anesthetic, the 

 operation and the kind of animal, as an artificially excited discharge 

 might be expected to do. This presumption is further strengthened by the 

 fact that when the rate of blood flow is altered within very wide limits it is 

 the concentration which varies and not the amount of epinephrin given off 

 per unit of time. 



Control of the Epinephrin Discharge by the 

 Nervous System 



The fact just noted would of itself be sufficient to dispose of the con- 

 tention of Popielski(fr) that the increased output caused by stimulation of 

 the splanchnic nerve is not a true secretion but is simply due to the wash- 

 ing out of more epinephrin when the blood flow through the gland is in- 

 creased by the excitation of the vasodilator fibers discovered by Biedl 

 (a) (1897) in the splanchnic and by the rise of pressure. His arguments 

 against the true secretory function of the splanchnics for the supra- 

 renal glands are entirely devoid of value. That pressure on or 

 manipulation of the glands liberates epinephrin is true enough, as was 

 shown by Stewart and by Stewart, Rogoff and Gibson (1916) (Fig. 6), 

 but it is quite erroneous to say that it does not pass into the circulation 

 until the gland is flushed out with blood, as after stimulation of the 

 splanchnic. He estimated, by testing (on rabbit intestine segments and by 

 injection into rabbits) blood withdrawn from the inferior vena cava by 

 a catheter during pressure upon the suprarenal, that the blood of a 13 

 kgm. dog would contain 2 mgm. of epinephrin. This would represent 



