OF IXSECTIVOROUS PLANTS 447 



Another set of experiments was made with hquor from non-stimulated 

 pitchers; unswoUen carmine fibrin was used, and no acid was added to 

 the reaction-mixture. The pitcher hcjuor was placed on the substrate, 

 and sufficient trikresol (2 percent, solution) was added to give a con- 

 centration of 0.2 percent, of the bactericide. Six experiments were 

 made, the volumes of pitcher liquor being 1.0, 1.5, 2.5, 3.0, 3.5 and 5.5 

 cc. respectively. Even after 70 days, the substrate was absolutely un- 

 attacked. The supernatent liquid had assumed a very faint pink tinge, 

 no more marked than that of a blank experiment. 



In a third set of experiments, unswollen carmine fibrin was incubated 

 with liquor from non-stimulated pitchers, in the presence of both hydro- 

 chloric acid and trikresol, as described above. Two experiments were 

 made, the volumes of pitcher liquor being 2.5 and 1.0 cc. respectively. 

 The substrate was markedly digested, in the first experiment in 16 

 hours, in the second experiment in 52 hours. 



Edestan 



The solution of edestan, used in these experiments, was prepared 

 by dissolving 0.1 gram of edestin in 15 cc. of 0.1 N hydrochloric acid, 

 previously diluted to 25 cc. with water. After the mixture of edestan 

 solution and pitcher liquor had been incubated under the conditions 

 stated below, it was neutralized with 0.1 .Y sodium hydroxide, using 

 phenolphthalein as the indicator. 



Liquor from stimulated pitchers was used in the following experiments: 



The pitcher liquor (20 cc.) was mixed with 25 cc. of edestan solution; 

 the mixture was diluted to a volume of 50 cc. with water, and was in- 

 cubated for 14 days. Then the solution was neutralized. The deter- 

 mination proper gave absolutely no precipitate, showing that proteolysis 

 had occurred, and that both the protean, edestan, and the meta-protein, 

 which is one of the first products of proteolysis, had been converted 

 into simpler proteolytic products. In the blank, on the other hand, 

 a voluminous precipitate formed. 



In a second experiment, 1 cc. of pitcher liquor and 2 cc. of the edes- 

 tan solution were mixed ; and the mixture was diluted with water to a 

 volume of 5 cc, then incubated for 8 days. On neutralization, the 

 determination proper failed to give a precipitate, while the blank yielded 

 a voluminous precipitate. Hence the edestan had been digested. 



Experiments were also made, using the liquor from non-stimulated 

 pitchers : — 



