PROTOZOA AND THE UTRICLES OF UTRICULARIA. 259 



of the injected bladders were not capable of bringing about the 

 death of the paramecia and might not have captured specimens if 

 placed in a culture medium containing them, or that the condition 

 of the bladders was modified in some way during the process of 

 injection. This subject will be referred to later. 



When injected into detached bladders paramecia may die within a 

 short period or remain alive for many days. Three experiments 

 furnish data regarding the death of paramecia injected into 

 detached bladders. 



Experiment n. From 2 to 12 paramecia were injected into 4 bladders. They 

 died in two bladders within 18 hours; escaped from one; and 9 specimens remained 

 alive in the remaining bladder for 14 days; these paramecia were evidently suffering 

 from lack of food. One of them remained alive for 16 days, but was gone (escaped?) 

 on the 1 7th day. 



Experiment M. 6. Six bladders were injected with from one to 6 paramecia 

 each. All were alive at the end of i| hours; all died within 6 hours except those 

 in one bladder which died within 22 hours. 



Experiment M. 12. Fifteen bladders were injected with paramecia. They died 

 in 10 bladders within 2 hours; in the other five they lived at least 2 days in 2, 



3 days in 2, and 5 days in one. 



These results are similar to those obtained by injecting para- 

 mecia into attached bladders and indicate that the separation 

 of bladders from the plant has no effect upon their relation to 

 the prey they capture. 



Paramecia captured by or injected into attached bladders that 

 have been irrigated with water usually die within several hours or 

 live for several days. The bladders were irrigated by first inserting 

 a fine pipette through the entrance and sucking out the contents. 

 Further suction was then applied which drew a continuous 

 stream of water into the bladder from the outside and up into 

 the pipette. The inside of the bladders was thus thoroughly 

 washed out and the bladders filled with fresh water. 



Experiment 58. Thirty-eight bladders on 5 branches were irrigated, placed in a 

 paramecium culture for if hours and then examined. Four bladders captured 

 paramecia. Bladder a contained 2 dead and one alive; b, 2 alive; c, 4 dead and 



4 alive; d, one alive. 



Experiment 62. Thirty-four bladders on 5 branches were irrigated, placed in a 

 paramecium culture for 2 hours and then examined. Five bladders were positive. 

 The paramecia escaped from 2 of the bladders; they were dead in 2 and alive 

 in one. 



Experiment 63. Only one of 39 bladders on 7 branches became infected with 

 paramecia; two specimens in this bladder died within 2 hours. 



