BASES DERIVED FROM THE PROTEINS 235 



Three years later, in the course of his investigations of 

 putrefaction bases, Ackermann (Zeitsch. physiol. Chem. 1910, 

 65, 504) infected a solution of histidine hydrochloride, to which 

 a little peptone and certain salts had been added, with a culture 

 from putrid pancreas and obtained after several weeks nearly 

 30 per cent, of the amount to be expected of the amine. At 

 the same time he isolated a small quantity of the above- 

 mentioned iminazolylpropionic acid. 



Neither of the investigations referred to, however, brought 

 to light the remarkable physiological properties of /3-iminazolyl- 

 ethylamine, which were not recognised until the base had been 

 identified among the active constituents of ergot by Barger 

 and Dale (Journ. Chem. Soc. 1910, 97, 2592). 



It was known that some preparations of ergot had a very 

 powerful effect in causing contraction of the isolated non- 

 pregnant uterus, yet neither of the two active principles which 

 had at that time been isolated (the alkaloid ergotoxine and the 

 putrefaction base /»-hydroxyphenylethylamine) could produce 

 the effect. Barger and Dale therefore continued their work 

 by searching for a third active principle, adopting as physio- 

 logical criterion the action on the isolated uterus as used 

 by Kehrer. In carrying out the experiment the uterus of 

 a freshly killed virgin cat or guinea-pig is suspended in a 

 bath of Ringer's solution, at 37 , which is oxygenated by passing 

 in gas from a cylinder. One end of the uterine horn is fastened 

 by means of a fixed platinum hook, whilst the other is suspended 

 by a similar hook and connected by means of a thin wire to 

 a delicate writing lever, which records the contractions of the 

 organ on a slowly revolving drum. Solutions are tested by 

 adding them in small quantities to the bath containing the uterus. 



Among the ergot preparations examined in this way by 

 Kehrer, one of the most active was found to be a dialysed 

 extract prepared by a method suggested by Wernich in 1872. 

 In making this " ergotinum dialysatum," Barger and Dale found 

 that the activity of the dialysate gradually increased beyond 

 that originally characteristic of the ergot ; the active principle 

 was therefore being formed, although no putrefaction took place 

 obviously. It was also found that commercial extracts of meat 

 (Liebig's) and of yeast produced the same physiological effect 

 to a slight extent and an examination of these by methods 

 devised by Kutscher and others afforded indications that the 



