126 HEPBURN— BIOCHEMICAL STUDIES OF 



Edestan was digested by the pitcher Hquor in the presence of 

 very dilute hydrochloric acid ; liquor from stimulated pitchers pro- 

 duced a more rapid digestion than did liquor from non-stimulated 

 pitchers. 



Liquor from both non-stimulated and stimulated pitchers usually 

 dissolved the protean of castor bean globulin in the presence of very 

 dilute hydrochloric acid. 



Jacoby's ricin was dissolved by liquor from both non-stimulated 

 and stimulated pitchers in the presence of very dilute hydrochloric 

 acid. 



Liquor from stimulated pitchers apparently produced cleavage 

 of glycyltry pto phane, when the period of incubation was sufficiently 

 long. 



Liquor from non-stimulated pitchers exerted proteolytic action 

 only in the presence of acid, failing to produce proteolysis in the 

 absence of acid. 



Liquor from stimulated pitchers exerted proteolytic action in 

 both the presence and the absence of acid. 



The manner in which stimulation causes the pitcher liquor to 

 acquire active proteolytic power is a field for further research. 

 Stimulation may produce a change in the hydrogen ion concentra- 

 tion^- and thus render the reaction favorable for the activity of a 

 protease already present in the pitcher liquor ; or it may cause the 

 activation of a zymogen already present ; or it may give rise to an 

 increased secretion of protease by the glands of the pitcher. 



In the presence of acid, certain substrates — especially edestan — 

 were digested by liquor from stimulated pitchers more rapidly than 

 by liquor from non-stimulated pitchers. 



The following conclusions are drawn from the bacteriological 

 studies : 



Liquor taken aseptically from unopened pitchers was sterile. 



12 Since this paper was presented, an abstract of a monograph by Jenny 

 Hempel entitled " Bidrag til Kiindskaben cm Succulenternes Fysiologi " 

 (Copenhagen, H. Hagerup, 1916, 147 pp.) has appeared in Physiological Ab- 

 stracts, 1917, II., 146 (issued in May, 1917). The following quotation is taken 

 from this abstract. "The sap of the stimulated pitcher of NcpcntJics gives 

 values for the hydrogen ion concentration greater than 10-'', but unstimulated 

 pitchers give no definite value." 



