THE PITCHER LIQUOR OF NEPENTHES. 125 



produced an alkaline reaction, i. e., a reddening of the medium. 

 This red coloration gradually spread from the colonies as centers 

 over the entire plate, and was quite marked, as a general rule, by 

 the third or fifth day. In those experiments in which colonies 

 developed but slowly, the red coloration was noted by the tenth day. 

 Hence the microorganisms produced basic compounds from the 

 substrates. During the last portion of the period of observation, 

 from the tenth to the fourteenth day of incubation, ofttimes the 

 medium changed in reaction and became acid to rosolic acid, never- 

 theless the colonies themselves remained alkaline. 



Inclvided in the above experiments was a group in which the 

 liquor from each of seven pitchers was plated on all four rosolic 

 acid agars — glycocoll, acetamide, asparagin, and ammonium lactate. 

 The bacteria grew and produced an alkaline reaction at about the 

 same rate in all four media. In these experiments, a record was 

 also kept of the odor of the cultures ; quite frequently the plates 

 were characterized on the third day by an odor recalling that of 

 ammonia or amines ; this odor was rarely present on the tenth day. 



Hence the microorganisms were able to utilize glycocoll, aceta- 

 mide, asparagin, and ammonium lactate, which formed their sole 

 source of carbon and nitrogen, and were able to produce basic 

 nitrogenous compounds from these substrates. 



General Summary. 



The following conclusions are based on the chemical studies : 

 Using the formol-titration, it was found that liquor from non- 

 stim.ulated pitchers lacked proteolytic power, while liquor from 

 stimulated pitchers produced proteolysis of a number of substrates : 

 ovalbumen, fibrin, ovomucoid, Nahrstoff Heyden, and Witte pep- 

 tone. In the presence of very dilute hydrochloric acid, edestan 

 was digested by liquor from stimulated pitchers, but not by that 

 from non-stimulated pitchers. 



Carmine fibrin was not dissolved by liquor from non-stimulated 

 pitchers in the absence of acid, but was digested and dissolved by 

 the liquor from both non-stimulated and stimulated pitchers when 

 0.2 per cent, of hydrochloric acid was present in the reaction 

 mixture. 



