264 K. \\ . HEGNER. 



Is the same factor that is responsible for the death of para- 

 mecium also responsible for its disintegration? 



Does the plant secrete something into the bladder that digests 

 the paramecia? 



It would be unprofitable to discuss these questions on the basis 

 of the data available but certain observations not emphasized 

 above have a bearing on them. In the first place, it is evident 

 that paramecia are not killed quickly by confinement, since in 

 some of the experiments specimens lived for several weeks in the 

 bladders. The physiological state of the plant apparently has a 

 large influence on the paramecia. For example, in Experiment 57 

 all the paramecia injected into bladders on one stem died within 

 a few hours and all injected into those on another stem were all 

 alive at the end of 24 hours. In another case (Experiment M. 13) 

 paramecia were injected into 6 irrigated bladders on each of 4 

 branches; they were all dead in the bladders on three of the 

 branches within 5 hours but remained alive in certain of the 

 bladders on the fourth branch for 8 days. These experiments 

 indicate that the plant when in the proper physiological condition 

 secretes something into the bladders that kills paramecia but at 

 other times simply confines the organisms within the bladders. 

 Attempts were made to determine whether or not the plant 

 exhibited evidences of hunger and satiety by examining bladders 

 continuously over a period of several days, but the results are 

 not significant. Another problem considered was the possible 

 selection of organisms by the bladders. No experimental data 

 are available on this point but the observations on the types of 

 organisms captured and on the method of capture led to the 

 conclusion that any organism may be captured that is small 

 enough to enter the vestibule of the bladder and actively moves 

 about within the vestibule. 



The best tests for the presence of digestive enzymes within 

 the bladder have been reported by von Luetzelburg (1910) who 

 comes to the conclusion that the organisms captured by the 

 bladders are utilized as food by the plant by means of an enzyme 

 acting in an alkaline medium. An admixture of acid (benzoic 

 acid) prevents the organisms from injuring the walls of the 

 bladder. Digestion within the bladder is slow but thorough. 



