74 MEDULLA 



regions of the body besides the adrenal. According to Elliott 181 

 the paraganglion aorticum of the newborn contains twenty-four 

 times as much epinephrine as both adrenals despite the twenty- 

 five-fold size of the latter. 393 In the dog, Kahn 344 found one- 

 twelfth to one-thirtieth as much epinephrine in the extra- 

 chromaphil tissue as in the adrenals. 



Many sympathetic ganglion cells also contain small amounts 

 of chromaphil tissue. 259 Whether or not these contain epi- 

 nephrine is doubtful. 209 The carotid sinus, although a chroma- 

 phil tissue, gives only a feeble reaction for epinephrine. 384 It 

 would thus appear that although chromaphil tissues may con- 

 tain epinephrine, this substance is not invariably present and 

 hence is probably not an indispensable mediator for their 

 activity. 



Epinephrine is not limited in its occurrence to the chroma- 

 phil system of the sympathetic ganglia but occurs in certain 

 secretions of reptilia. The skin-glands of the toad, Bafo agua, 

 contain about 5 per cent Zeyo-epinephrine as Abel and Macht 2 

 demonstrated. Certain poisonous Chinese toads also contain 

 epinephrine in their skin glands. 339 The skin glands of the 

 European and North American toad contain none. Histo- 

 logical investigations also indicate epinephrine to be present 

 in many invertebrates; e.g. in leeches in which six chromaphil 

 cells are present in the ganglia of the central nervous system. 

 In certain molluscs as in the mantle of Purpura lapillus, 

 chromaphil tissue, extracts of which manifest an epinephrine- 

 like action, are also present. 639 



ISOLATION AND STRUCTURE OF EPINEPHRINE 



Abel 1 first applied the term epinephrine to a crystalline 

 compound which he obtained from the adrenal gland and 

 which he considered to be its active principle. Subsequent 

 work showed Abel's compound to be the A^-benzoyl derivative 

 of the active principle, but the term epinephrine has been re- 

 tained for the base itself. Aldrich 9 and Takamine 618 in 1901 

 first isolated epinephrine as the free base. They called their 



