294 PROTEIN POISONS 



an anesthetized animal, washed, scraped, and worked up 

 immediately gives an extract with the characteristic physio- 

 logical action of /3-i. Bayliss and Starling showed that the 

 depressor substance could be extracted from fresh mucous 

 membrane of the dog's intestine by alcohol. It must 

 probably, then, be regarded as a normal product of intes- 

 tinal mucosa, though whether it is present in living cells, 

 or only formed when these are killed and disintegrated, 

 remains uncertain." 



/3-i has recently become a commercial product under the 

 name "ergamin;" it is also known as "histamin." 



Mellanby and Twort 1 have confirmed Ackerman's findings 2 

 that histidin is converted into ergamin by bacterial agencies, 

 and have demonstrated that it is formed in this way in 

 the alimentary canal. They have isolated a bacillus which 

 causes this conversion : " It is a small bacillus with rounded 

 ends, non-motile, and Gram-negative. It will grow aero- 

 bically or anaerobically on the ordinary laboratory media. 

 The optimum temperature is about 37. The growth on 

 gelatin, agar, and broth is similar to that of bacillus coli. 

 Milk is clotted and no liquefaction of gelatin takes place. 

 Acid and gas are produced in media containing glucose, 

 lactose, or dulcite." "In the alimentary canal of a guinea- 

 pig, at least, and probably in that of most mammals, the 

 bacillus capable of producing /3-i from histidin is present 

 from the duodenum downward. It is legitimate, therefore, 

 to assume that the presence of the histidin base, described 

 by Barger and Dale, is due to bacterial decomposition 

 going on in the intestine." It grows and produces ergamin 

 in alkaline Ringer's solution containing 0.1 per cent, of 

 histidin. When the concentration of the histidin is greater, 

 the growth is not so prompt nor the conversion so com- 

 plete. "It is evident that the toxic symptoms produced 

 by the substance together with its presence in the alimentary 

 tract must bring it under consideration as a possible cause 



1 Jour. Physiol., 1912, xlv, 53. 



2 Zeitsch. f. physiol. Chemie, 1910, Ixv, 504. 



