ENDOMIXIS IN PARAMECIUM AURELIA. 



455 



Thus clearly, in the long run, the 5 environment had no 

 effect on the periodicity of the process. But, as pointed out 

 before, endomixis appeared without exception in the four 5 

 cultures immediately upon their isolation from the respective 

 parent cultures and on subjection to the stale culture fluid. 

 Therefore, now that it is possible to compare parent and daughter 

 lines, the obvious conclusion from the data is that endomixis 

 was brought about earlier (except in -Bs which was started during 

 endomixis) by the changed cultural conditions; that is, earlier 



FIG. 9. 



than it appeared in the parent cultures. This result, it may be 

 noted, substantiates the conclusion from the former experiments 

 that the remarkably exact synchronism of endomixis of various 

 races under the most diverse environmental conditions is due to 

 a slight initial influence on the occurrence of the process. 



Figs. 9, 10, II and 12 show that the treatment to which the 

 s cultures were subjected resulted in a distinctly lower rate of 



1 Not studied cytologically during this period. 



