26(> R. W. HEGXER. 



* 



Experiment 64. Only-one of 31 bladders on 5 branches became infected; the 

 two specimens in this bladder died within 2 hours. 



Experiment M. IT. Six bladders on each of 4 branches were irrigated and then 

 inoculated with paramecia. All were alive at the end of i^ hours. After 9 hours 

 the paramecia were dead in IQ bladders, alive in 4, and had escaped through a 

 break in the wall of one. At the end of 24 hours the paramecia were dead in 22 

 and alive in one bladder. 



Experiment M. 13. Six bladders on each of 4 branches were irrigated and then 

 inoculated with paramecia. All were alive after 25 hours. At the end of 45 

 hours all were alive in the bladders on brancli d, all were dead on branch b, and 5 

 were dead and one alive on branches a and c . 



Experiment M. i~. Four branches bearing 6 bladders each wen- used. Bladders 

 i, 2, and 3 on each branch were irrigated and bladders 2, 4, and 6 were not; all 

 were inoculated with paramecia. All were alive at the end of one hour. After 

 2\ hours all were dead on branch b; all were alive on branch </; all were dead in 

 bladders i, 3, 4 and 5 of branch a and in 4 and 6 of branch c. Paramecia remained 

 alive for 54 hours in bladder 6 of branch a, in bladders i, 2, and 3 of branch c, and 

 in bladders I, 3, and 5 of branch d. These all died within the next 4 days. 



These experiments indicate that irrigated bladders do not 

 succeed well in capturing paramecia but that the specimens 

 captured usually die within 2 hours. Their failure to capture 

 paramecia is due probably to the fact that many irrigated 

 bladders do not take on the compressed condition necessary for 

 capturing their prey (see page 243). Exps. M. n and M. 13 

 prove that paramecia inoculated into irrigated bladders usually 

 live for several hours but that many of them die within from \\ 

 to 9 hours. Differences in the physiological condition of the 

 different branches seems to be responsible for the fact that the 

 paramecia die in all the bladders on one branch but remain alive 

 in all those on another, as in Exp. M. 13 branches d and b. In 

 Exp. M. 17 a critical experiment of irrigated and non-irrigated 

 bladders is made. Very little difference is noticeable at the 

 end of 2\ hours at which time the paramecia were dead in 6 

 irrigated and in only 2 non-irrigated bladders. The data indicate 

 that irrigation delays but does not prevent the death of the 

 paramecia. 



Paramecia break down into a granular mass in attached or 

 detached bladders that have captured them or into which they have 

 been inoculated either with or without irrigation. The paramecia 

 that die in the bladders of utrictilaria undergo disintegration in 

 several different ways. Some of them dissolve into a mass of 

 granules almost at once, spreading out as though an explosion 



