PERIODIC REORGANIZATION IN PARAMAECIUM 



475 



Text figure 15 



curred (it is impossible to prove this since he employed mass 

 cultures in the work) then it is also true that he discovered at 

 least one of the steps in the process which is outlined in the pre- 

 sent paper but obviously he failed to recognize its general funda- 

 mental importance. This is evident from the trend of his work 

 and that of his students, on the life history of Infusoria, during 

 the subsequent quarter of a century. 



Another question naturally suggests itself at this point: Is 

 the process confined to Paramaecium aurelia? Figure 34 (pi. 

 3) is from a pedigreed race of Paramaecium caudatum which we 

 have studied by the same experimental methods, and shows a 

 characteristic stage in the process. This indicates that it occurs, 

 at least with essentially similar features, in Paramaecium cau- 

 datum also. It will be shown in a later section of this paper 

 that certain of the morphological changes interpreted by Calkins, 

 Popoff and others as degeneration phenomena in Paramaecium 

 caudatum are in all probability the same process. It may be 

 mentioned here, however, that Doflein ('07) figures an abnormal 

 conjugating pair of Paramaecium caudatum, one animal of which 

 appears to be a typical vegetative animal while the other shows 

 what he interprets as conjugation nuclear phenomena in a single 



