228 SCIENCE PROGRESS 



shown that the action observed by Abelous was exercised both 

 by zsoamylamine and /-hydroxyphenylethylamine. The former 

 of these bases is soluble in chloroform and yields Abelous's 

 crystalline hydrochloride; it is probably also present in placenta ; 

 it is relatively abundant in extracts of putrid meat but it is not 

 very active. The latter base is much less abundant in putrid 

 meat and is insoluble in chloroform ; whilst it has an action 

 resembling that of zso-amylamine, it is much more powerful. 



It was, of course, probable that during putrefaction />-hydroxy- 

 phenylethylamine is formed directly from tyrosine ; this surmise 

 was proved to be correct by Barger and Walpole, who grew 

 putrefactive bacteria in a solution of pure tyrosine in broth. 

 The chief physiological effect of ^-hydroxyphenylethylamine, 

 namely its power of raising arterial blood pressure, had been 

 observed previously in certain aqueous extracts of ergot : 

 Barger and Dale {Proc. Physiol. Soc. May 15, 1909) were able 

 to show that the base is also present in extracts of ergot and 

 that it causes the pressor action and contributes to the action 

 on the uterus. It may be that some of the base is only formed 

 during the process of extraction but a certain amount is un- 

 doubtedly present in fresh ergot together with several other 

 putrefaction bases. 



It is very probable that />-hydroxyphenylethylamine is formed 

 by putrefaction in the human intestine and it is conceivable 

 that this substance is the cause of the persistent high blood 

 pressure observed in certain persons. Metschnikoff has attri- 

 buted the degeneration of the arteries in old age (arterio- 

 sclerosis) to this high blood pressure, which he considers is a 

 consequence of intestinal putrefaction ; hence he has advocated 

 the use of sour milk, in order that the lactic acid bacilli con- 

 tained in it may drive out the putrefactive bacteria. Metschnikoff 

 claims that, by thus limiting intestinal putrefaction, man should 

 be able to attain a greater age than he does at present. Now it 

 is not known whether /»-hydroxyphenylethylamine can produce 

 arterio-sclerosis but of all putrefaction products hitherto exa- 

 mined this base has the most powerful pressor action ; further- 

 more, arterio-sclerosis can be induced experimentally by repeated 

 injections of another pressor substance, namely adrenaline. If 

 therefore we adopt MetschnikofT's theory, we cannot neglect the 

 possibility that />-hydroxyphenylethylamine is a natural poison 

 and one which contributes to the shortening of human life. 



