i BE vi -K I nai. QLAND8 - 13 



noted (Fig. L92 . If 1 1 1 « - fluid added to the inflowing fluid contains epi- 

 nephrine, the outflow will become diminished. This is a \ 

 method, although it is Bomewhal limited in Bcope unless Large frogs are 

 procurable, because of the difficulty <>t' «_r « • 1 1 i 1 1 «_r the necessary cannula? 

 into the vessels (aorta and abdominal vein). 



5. The pupil of tl>> enucleated < >i< of thi frog. Extremely small trac 

 of epinephrine are observed to cause a dilatation. 



6. 77/< denervated iris. Tfie fluid to be tested is placed in the conjunc- 

 tival s;ic of an animal from which the superior cervical ganglion <>f the 

 corresponding side has been removed sum.- days previously. Under such 

 conditions, if epinephrine is present in the fluid, dilatation of the pupil 

 occurs. I'.oth of the preceding reactions we owe to Meltzer. 7 ' 



It should ho emphasized that, although each of these methods is in 

 itself vn-y sensitive for the detection of epinephrine without being al- 

 ways specific, yet the result should not be considered conclusive unl< 

 definite effects have been secured hy at least two methods that are ''' s 

 far as possible independent of each other. 



As an outcome of investigations by these methods it has been found 

 that, when blood from the adrenal vein is collected in a pocket of vena 

 cava made by applying clamps above and below the entrance of the 

 adrenal veins, the presence of epinephrine can be revealed, the rate 

 secretion being from 0.0003 to 0.001 mer. per kilogram of body weighl 

 per minute (Stewart and Bogoff). The absolute amount of epinephrine 

 liberated from the gland can be measured only by finding the concen- 

 tration in the adrenal vein blood and the rate of bloodflow. This amount 

 is approximately constant, so that the concentration in the blood which 

 collects in the cava pocket varies inversely with the rate of bloodflow. 

 In asphyxia the bloodflow is d< \ so thai the concentration 



nephrine increases, bu1 there is no change in the absolute amount. N 

 ther anesthesia nor trauma affects the amount. The concentration is 

 likely to rise late in an experiment because of the slowing of bloodflow. 

 Adrenal activity may, however, be excited by massage of the trland'. 

 by stimulation of its nerve supply through the greal splanchnic nerve 



The presence of epinephrine in hi 1 collected directly from the adrenal 



veins does nol justify us in concluding that, when mixed with the 

 mainder of the hi I in the body, there would be a sufficient concentra- 

 tion of this substance to develop any of its activities. It has th< 

 been necessary to devise methods by which this possibility could be 

 tested. 



The Autoinjection Method. Such a method was first of all 

 fully used by Asher, who employed an animal from which all the abdom- 

 inal viscera had 1 n removed. On stimulation of the g splanchnic 



