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S. O. MAST 



The results obtained in our experiments with Didinium do not 

 support these contentions. We have already demonstrated that 

 conjugation in Didinium causes only a shght decrease in the 

 rate of fission, if any at all, and in this and the following sections 



TABLE 2 

 The effect of conjugation on death-rate 

 Conjugants separated signifies that conjugants were mechanically separated 

 before fertilization; small signifies that the individuals were ready to conjugate; 

 and large that they were not ready to conjugate. The numbers in all cases 

 refer to individuals, not to pairs. The number died includes all individuals 

 which did not divide after conjugation or after they were isolate, in case there 

 was no conjugation. 



it will be demonstrated that it causes no appreciable increase in 

 variation in the rate of fission or in death-rate. 



The results obtained on the relation between conjugation and 

 death-rate are, as previously stated, presented in brief form in 

 table 1. A portion of these results is given in detail in table 2. 

 This table contains a record of all isolated ex-conjugants which 

 died without fission and of all other isolated specimens which 



