ENDOMIXIS IN PARAMECIUM AURELIA. 



447 



words that the cell has undergone the preliminary stages of 

 endomixis which ordinarily call forth the observable nuclear 

 changes ljut that in the cases in hand the latter were never 

 realized. This is equivalent to making the term endomixis 

 coextensive with the term rhythm the term rhythm denoting 

 the physiological effect as indicated in the reproductive activity, 

 while the term endomixis covers all the underlying physiological 



FIG. 5. 



changes together with the definitive nuclear phenomena charac- 

 teristic of the low point in the division rate. The term endomixis 

 was not used in that broad sense when first employed by Woodruff 

 and Erdmann and it is unprofitable to extend it now. Applying 

 the term strictly to the complicated reorganization process of 

 the cell does not deny the undoubted 'fact that these changes 

 are but the expression of the climax of a series, of physiological 

 phenomena which probably extend back to the consummation 

 of the previous endomictic period. So, it seems to be a more or 

 less academic ' question whether rhythms and endomixis are 

 independent. Certainly the rhythms occur for a while without 

 endomixis in sensu stricto but in all such cases the culture has 

 died before very long. 



