254 R- w . HEGXER. 



about the death and disintegration of paramecia, and that any 

 digestive ferments that might have been produced by the bladder 

 stimulated by the presence of paramecia, are not injurious to the 

 euglenas. 



Liquid from bladders which have captured and killed paramecia 

 does not kill euglenas. In Experiment 36, the liquid was squeezed 

 out of 25 bladders that had captured and killed paramecia. 

 Euglenas added to this liquid were still active 18 hours later. 



EXPERIMENTS WITH PARAMECIA. 



The bladders of utricularia capture and kill paramecia. A 

 preliminary experiment proved that paramecia are readily 

 captured and killed by utricularia bladders. 



Experiment i. A branch bearing 14 bladders was immersed in a culture con- 

 taining large numbers of paramecia. When examined on the following day, 22 

 hours later, all bladders were found to contain paramecia only one of which was 

 alive. It was evident that a number of specimens had disintegrated so the exact 

 number captured could not be determined, but there were at least 4 bladders 

 with one specimen each, 3 with 2, 5 with 3, and 2 with 5. The specimen that was 

 still alive died within one hour and was beginning to disintegrate 2 hours later. 

 On the next day, 48 hours after the experiment was begun, the onlj' traces of 

 paramecia remaining in the bladders, which had in the meantime been taken out 

 of the paramecium culture, were fine granular masses representing thoroughly 

 disintegrated paramecia. It is evident from this experiment that protozoa as 

 small as paramecium are captured by the bladders and are killed and disintegrate 

 within a few hours. 



Paramecia are captured by either bladders that are attached to or 

 detached from the utricularia plant in as short a time as 8 minutes. 

 Branches bearing bladders were placed in paramecium cultures 

 or bladders were detached from the plant and immersed. They 

 were taken out; washed in water, and examined at various 

 intervals. The following data were obtained from 8 experiments. 



Total number of bladders 180 



Total number positive for paramecia 56 or 30% 



Total number negative for paramecia 124 or 70% 



Numljer of bladders attached to plant 150 



Number of attached bladders positive for paramecia 47 or 30% 



Number of detached bladders 30 



Number of detached bladders positive for paramecia 9 or 30% 



Time required to capture paramecia, from 8 minutes to 2 hours; average 56 minutes. 

 Time required for attached bladders to capture paramecium, from 30 minutes to i^ 

 hours; average, 56 minutes. 



