BASES DERIVED FROM THE PROTEINS 227 



1902, 1, 507) from those of prolonged peptic digestion. It may be 

 doubted whether the experiments were carried on under sterile 

 conditions. The base was found also in Cheddar cheese by 

 Van Slyke and Hart {Amer. Chem.J. 1903, 30, 8) and in Emmen- 

 thaler cheese by Winterstein and Kunz {Zeitsch. physiol. Chem. 

 1909, 59, 138); the writer has extracted relatively large quantities 

 from Gruyere cheese. Gautier {Bull. Soc. Chem. 1906 [Hi.], 35, 

 1 195) obtained the base from putrid cod-livers, the source of 

 the old-fashioned dark-coloured cod-liver oil. 



In all these investigations, however, the marked physio- 

 logical activity of />-hydroxyphenylethylamine was overlooked, 

 probably because it was not expected that the inert amino-acid 

 tyrosine would give rise to a physiologically active substance 

 when deprived of the carboxyl group. Physiological activity 

 was first associated with the base when Barger and Walpole 

 {Journ. Physiol. 1909, 38, 343) recognised that it was the chief 

 pressor principle in extracts of putrid meat. 



It may be of interest to mention the steps which led to the 

 latter investigation. In tracing the manner in which adrenaline 

 (adrenine) — the pressor principle characteristic of the adrenal 

 gland — is formed, the French physiologist Abelous and his 

 pupils found that the activity of the gland increased on incuba- 

 tion with meat; subsequently {C. R. Soc. de Biol. 1906, 1, pp. 463, 

 530) they observed that an extract of horse-meat which had 

 been incubated and putrefied by itself raised arterial blood 

 pressure when injected intravenously. They obtained an im- 

 pure hydrochloride of a base which was soluble in chloro- 

 form which exercised a marked pressor action ; they did not 

 identify the base. Subsequently, Dixon and Taylor {Brit. Med. 

 Journ. 1907, ii. p. 1150), influenced doubtless by the discovery 

 of secretin and other hormones — investigated the action of 

 extracts of human placenta and found that such extracts injected 

 intravenously caused a rise of blood pressure and also contrac- 

 tion of the pregnant uterus. Then it was found by Rosenheim, 

 who attempted to isolate this active principle of the placenta, 

 that only the more or less putrefied placenta gave active extracts, 

 those from the fresh or merely autolysed organ being inactive ; 

 Rosenheim was thus led to the view that a substance was present 

 in the putrid placenta identical with that obtained by Abelous 

 and his collaborators from putrid meat ; the identification of this 

 substance only became possible after Barger and Walpole had 



