PERIODIC REORGANIZATION IN PARAMAECIUM 497 



From the life history of this race of Paramaecium aureha we 

 'lean toward the view that both endomixis and conjugation in the 

 infusorian, as fertilization in higher forms, have a two-fold sig- 

 nificance — both afford the opportunity for molecular rearrange- 

 ment which leads to increased physiological activity, and the 

 opportunity for variation. The life of the paramaecium race 

 can proceed indefinitely with endomixis under favorable environ- 

 mental conditions — conjugation being unnecessary. ''Senile de- 

 generation" and ''physiological death" are not the inevitable 

 result of continued reproduction without conjugation — the cell 

 has an internal regulatory phenomenon, endomixis, which 

 is self-sufficient for the indefinite life of the race. 



From whatever standpoint one views the wealth of data which 

 has been secured during recent years in regard to the problems 

 of variation, heredity, and the significance of conjugation in 

 Protista, it is clear that hereafter, in the interpretation of previous 

 and the prosecution of subsequent studies, due weight must be 

 accorded to endomixis. 



