82 THE SIMPLER NATURAL BASES 



blood pressure caused by extirpation of both supra-renals could be 

 raised temporarily by an injection of an extract of the gland. Cybulski 

 [1895], wno continued the investigation, also obtained a pressor 

 action with blood from the supra-renal vein. The isolation of the active 

 principle was now attempted by several investigators. Moore [1895- 

 97] working in Schafer's laboratory, soon found that the physiological 

 activity of extracts went parallel with the intensity with which they 

 gave Vulpian's colour reactions and concluded that the chromogen was 

 identical with the active principle. Attempts to isolate it were made 

 by Frankel, Muhlmann [1906], Gurber [1897], and especially by 

 Abel and Crawford [1897], Abel [1898-1901], and by von Fiirth 

 [1898-1901], but these attempts were all unsuccessful. Von Fiirth, 

 indeed, obtained a highly active preparation of the substance, which 

 he termed suprarenin, by precipitating it as iron compound by the 

 addition of ferric chloride to a purified extract in methyl alcoholic 

 solution, and Abel separated the active principle as benzoyl derivative, 

 but he could not recover it in a pure state by subsequent hydrolysis. 

 Abel's work, however, led to the crystallisation of the active principle 

 by Takamine [1903, 1-3] who named it "adrenalin," and very soon 

 afterwards it was obtained independently by Aldrich [1901] who as- 

 signed to it the correct empirical formula C 9 H 13 O 3 N. 



The chemical constitution of adrenaline could now be investigated. 

 On fusion with potash Takamine had already obtained from it two 

 substances which he regarded as catechol and protocatechuic acid. 

 Von Fiirth confirmed the production of the latter substance and also 

 showed that a methylamino-group and an alcoholic hydroxyl are present. 

 Abel for a long time defended the erroneous formula C 10 H 13 NO 3 , |H 2 O 

 and termed the crystalline active principle " epinephrin hydrate ". The 

 substance obtained on complete hydrolysis of his benzoyl derivative 

 he considered to have the composition C 10 H 13 NO 3 , and this he called 

 " epinephrin," but found later that it was chemically and physiologi- 

 cally different from the active principle of the gland. Abel's formula 

 was disproved conclusively in favour of that of Aldrich by Pauly 

 [1903], who analysed very carefully purified material and also showed 

 that adrenaline contains an asymmetric carbon atom. Pauly reduced 

 the number of possible constitutional formulae to two, viz. : 

 OH OH 



>OH 



and II 



CHOH CH . NH . CH S 



CHg.NH.CHg CH 2 OH 



