I ill IDRENAL GLAN 745 



In connection with these observations it is of interest to note that dur- 

 ing stimulation of the Bplanchnic nerve in a normal animal, the eoi 



quenl rise in hi I pressure shows two pea Pig 29, page 137 . The 



first is no doubl due to dired stimulati >f the splanchnic vasoconstric- 

 tors, and the second to the outpouring of epinephrine into the blood, the 

 justification for this conclusion being thai the latter rise fails to app< 

 after removal of the adrenal glands. 



Taking the results as a whole, it is indeed doubtful whether under nor- 

 mal conditions a sufficienl amounl of epinephrine is discharged into the 

 blood of the vena cava to affed appreciably the tone of the blood vessels. 

 and ihis conclusion seems all the more justified because of the fad thai 

 small quantities <>f epinephrine have a dilating rather than a constricting 

 influence, at leasl on certain vessels (Hartman**). It may be, however, that 

 the maintenam t' vascular tone under certain conditions is greatly as- 

 sisted by the presence of epinephrine in the hi I. similarly the sympa- 

 thetic control of other functions may be facilitated by the presence 

 small amounts. It has been found, for example, that, although stimula- 

 tion of the celiac plexus causes the glj cogen stored in the liver to be con- 

 verted into sugar, this result is qoI as a rule obtained <»u stimulating 

 the plexus shortly after removal of the adrenal glands. The presence 

 of epinephrine in the blood would, therefore, seem to be necessary to bring 

 aboul functional activity of the sympathetic nerve endings concerned in 

 the glycogenolytic process see page 637 , 



Adrenalemia. — In the lighl of these researches it is important to point 

 out that a greal pari of the work done by clinical observers purporting to 



show thai in such conditions as nephritis and arteriosclerosis there is an 



increase of epinephrine in the blood, has been found by Stewart and 

 others, using controlled methods, to be entirely unproven. 7 Some ur 

 tigators, however, still hold that temporary conditions, such as transient 

 rises of arterial blood pressure or temporary glycosuria, may sometimes 

 due to increased adrenal discharge into the blood. 



Ephinephrine has been thoughl to be a substance which is - id into 



the blood in supernormal amount when certain emergencies arise, the most 



important of these being fright, or some other extreme .'motion. This 



belief has arisen partly from the similarity in the general behavior 

 of an animal following the intravenous injection "f epinephrine and dur- 

 ing stales of extreme excitement. Dilatation of the pupils, bristling of 

 the hair, salivation, rise in arterial blood pressure, inhibition of the ii 

 tmal movements, protrusion of the eyeballs are all symptoms of tear ju^ - 

 they arc of epinephrine injection. Impressed by these resemblances Can- 

 non 7 ' undertook an extended research to test the hypothesis thai the reac 



lion of an animal to fear and other emotional stales is partly dependent on 



