OF INSECTIVOROUS PLANTS 445 



Nahrstoff-Heyden (15 cc. of a 1 percent, aqueous solution) was 

 mixed with 15 cc. of pitcher liquor, then incubated for 3 days. The 

 formol titration was:- determination proper 0.30 cc, blank 0.10 cc. 

 0.1 N sodium hydroxide. 



Witte peptone (25 cc. of a 1 percent, aqueous solution) was mixed 

 with 25 cc. of pitcher liquor, then incubated for 4 days. The formol 

 titration was: — determination proper 4.60 cc, blank 1.85 cc. 0.1 .Y 

 sodium hydroxide. 



A solution of edestan was prepared by dissolving 0.1 gram of edestin 

 in 15 cc. of 0.1 .Y hydrochloric acid, previously diluted to 50 cc. with 

 water. The pitcher liquor (8 cc.) was mixed with 25 cc. of this solu- 

 tion (equal to 0.05 gram of edestin), and then incubated for 25 days. 

 The formol titration was: — determination proper 0.90 cc, blank 0.00 

 cc. 0.1 A' sodium hydroxide. 



When liquor from non-stimulated pitchers was used, the following 

 results were obtained. 



In three experiments, the period of incubation was 4 days. In the 

 first experiment, 10 cc. of pitcher liquor and 0.05 gram of ovalbumen 

 were used; in the second experiment, 12.5 cc. of pitcher liquor and 25 

 cc. of a 1 percent, aqueous solution of Nahrstoff-Heyden; in the third 

 experiment, 12.5 cc. of pitcher liquor and 25 cc. of a 1 percent 

 aqueous solution of peptone (Witte). In all three experiments, the 

 formol titration of the determination proper was the same as that of the 

 blank, showing that enzymic cleavage of the substrates had not occurred. 



A solution of edestan was prepared by dissolving 0.1 gram of edestin 

 in 15 cc. of 0.1 N hydrochloric acid, previously diluted with water to a 

 volume of 25 cc. In one experiment, 25 cc. of the edestan solution 

 were mixed with 11.5 cc. of pitcher hquor; sufficient water was added to 

 make a total volume of 50 cc, and the solution was digested for 28 days. 

 In another experiment, 9 cc. of the edestan solution were added to 8 cc 

 of pitcher liquor; sufficient water was added to make a total volimie of 

 25 cc, and the solution was incubated for 21 days. In both experiments, 

 both the determination proper and the blank remained neutral, after 

 neutral formol had been added in the formol titration, hence digestion 

 with the production of soluble proteolytic products had not occurred. 



Carmine Fibrin 



The directions of Grutzner (22) for the use of this reagent were some- 

 somewhat modified. The carmine fibrin was washed with water to re- 

 move the glycerol, in which it had been preserved, then was permitted to 



