PERIODIC REORGANIZATION IN PARAMAECIUM 



467 



which result from two divisions in forty-eight hours. The fourth 

 animal (F4) was lost. Since each of the three animals preserved 

 has one macronuclear anlage it is certain that each of the two 

 parent cells in the 4173d generation had too macronuclear an- 

 lagen, one of which passed to each daughter cell at division. 

 The fourth animal (F4) which was lost during preparation obvi- 

 ously must have been in the same stage as those figured. The 

 next text figure, 11 (Gi to G3), shows again that at least seven 

 or eight generations are necessary to complete the process. The 



F, 



F4 



VI b 4174i 



VI b 41742 VI b 41743 



Text figure 10 



VI b 4174. 



animals are from Line Vlf in the 4184th, 4188th, and 4191st 

 generation and show the extrusion of the chromatin bodies from 

 the old macronucleus, the new macronuclear anlagen and the 

 nearly reorganized paramaecium cell. 



The last occurrence of the process in Line VI extended from 

 the 4229th generation to the death of the line at the 4231st gen- 

 eration from the accidental infection of the culture medium with 

 a deleterious strain of bacteria, as mentioned on pages 478 and 

 489. Five times in 21 1 generations the cell reorganized its nuclear 



