686 AKTHUK ISAAC KENDALL 



Barger and Walpole have detected tyramin in meat that lias heen 

 allowed to putrefy spontaneously. It appears to he a physiologically active 

 substance that is formed in small quantities when ordinary putrefactive 

 organisms are allowed to act upon protein in. the absence of utilizable 

 carbohydrates. Such a condition appears to be present in the alimentary 

 tract of man not infrequently. When tyramin is injected intravenously in 

 small amounts into dogs, it raises the blood pressure rapidly and decidedly. 

 The same authors have shown that this substance is also an important 

 pressor constituent in some ergot preparations. 



Pheuylethylamin, derived very probably from phenyl alanin, as 

 paraoxyphenyl ethylamin is derived from tyrosin, is" perhaps a pressor 

 base, although convincing data upon this point is wanting. 



Similarly, histidin, through the loss of the carboxyl group, becomes the 

 powerfully reactive histamin, or beta imidazole ethylamin. 



H H 



/ K 



H C N H C N 



> C - H -* m ) 



C N C N 



I I 



CH 2 . CIINH, . COOH CH 2 . CH 2 IS T H 



C H + CO, 



Ackermann has detected histamin among the products resulting from 

 the decomposition of histidin by bacterial action. Somewhat later, Ber- 

 thelot and Bertrand described their Bacillus aminophilus intestinalis, an 

 intestinal parasite belonging to the Mucosus capsulatus group, which they 

 believed to be the causative agent in the production of histamin in the 

 alimentary canal. About the same time, Mellanby and Twort isolated an 

 organism, apparently closely related to, if not identical with, Bacillus 

 coli, which effects the same transformation. The year before, Barger and 

 Dale had isolated histamin from the intestinal wall. Koessler and 

 Hanke have shown recently that Bacillus coli will produce histamin from 

 histidin in cultures of this organism. 



Ij is significant that both Berthelot and Bertrand and Mellanby and 

 Twort have found that the amin is not produced in acid solutions. A 

 survey of the experiments suggests strongly that the acid which is present 

 in such cases is derived from the fermentation of glucose. Histamin 

 is best isolated from "putrefying" mixtures. In this connection, the ob- 

 servation of Garcia that glucose added to putrefying horseflesh reduces 

 the yield of diamins very materially is significant. It would appear 

 that utilizable carbohydrates interfere with the utilization of the protein 

 or protein derivatives for energy, precisely as is the case with other putre- 

 faction products described above. 



