i ill \hi;i N \l. GLAN 



pressure produced by the injection is then ;i very fair measure of the 



amount of epinephrine contai ! in it. It lias been shown that the re- 



suits obtained by the chemical method agree very closely with those obtau 

 by the physiological, bul it should be remarked thai it is difficult to Bee how 

 the physiological method could be accurate in all cases, sine- it has been 

 shown that with greal dilution of epinephrine a reversed effed a vj 

 dilatation- may be obtained. Attempts to assay the strength of an 

 epinephrine solution by investigating the effects which it produe 

 other preparations, Buch as isolated loops of intestine or uterus, or the 

 enucleated eyeball of the frog, arc not always successful, sim effects 



are no1 alone dependenl on the concentration of epinephrine in the 

 extract. When such preparations are used for quantitative purpos 



the strength of the extract may be judged by finding tl stent to which 



it can be diluted and still remain active. 



Quite apart from the foregoing possible sources of error, it musl be 

 remembered that the results merely give us an idea of how much epineph- 

 rine may have been contained in the gland at the limo of its excision. 

 They can not tell us how much epinephrine the gland was secreting. Prior 

 to excision as much of this hormone mighl have been undergoing a proc< ss 

 of manufacture in the gland as was being discharged from it, so thai the 

 yed amount would represenl merely the balance of production and loss 

 of hormone by the gland. We mighl quite well find that the amount of 

 epinephrine in the excised gland was normal under conditions wl 

 there had been an excessive discharge of it into the blood; that is to say. 



- and production mighl have been equal. Where, however, a marl 

 deficiency is found to exist, it probably indicates that exhaustion of the 

 power of producing epinephrine was taking place. 



The Epinephrine Content of the Blood. The second method, in which 

 blood from one animal is tested for its epinephrine effed by intravenous 

 injection into another animal or by applying it to some isolated prepara- 

 tion on which epinephrine ads. has yielded important results. Since 

 serum contains all the epinephrine of blood, it can be conveniently used 

 for the tests Stewart and Rogoff). The isolated physiological prepara- 

 tions that have been used in testing for epinephrine in the animal fluids 



are as follow B: 



1. .1 segment of the small intestim of a rabbit, suspended in oxj -• 

 ated Locke's solution at body temperatu 



2. .1 segment of the uterus of a nonpregnant rabbit similarly prepaid 

 The apparatus used for observing the contractions of either prepara- 

 tion consists of a small glass chamber furnished below with a hook to 

 which one end of the segmenl is attached, the other end bej 



