PERIODIC REORGANIZATION IN PARAMAECIUM 443 



bearings of these cases (cf. p. 483) but merely to emphasize the 

 fact that the multipUcation of the micronuclei in an isolated cell 

 is not an infrequent event, and that the fate of the cell alone gives 

 the significance of the phenomena. 



B.* CLIMAX 



The period of the reorganization process, designated the climax, 

 is the most important of the three phases. Morphologically 

 defined it extends from the total disintegration of the old macro- 

 nucleus to the formation of the new macronuclear anlagen. Phys- 

 iologically speaking it represents a stage in which the vegetative 

 functions of the cell are relatively in abeyance and only the 

 potentiahties of the micronuclei are in evidence. At the end 

 of the descending phase the paramaecium cell possesses eight 

 micronuclei, twenty to thirty spherical chromatin bodies and 

 the membranous remains of the old macronucleus (fig. 14, pi. 2). 

 Figure 13 (pi. 1) gives an animal just as the degeneration 

 of the micronuclei sets in. It shows six micronuclei, one of 

 which is dividing, scattered in the cell, and numerous chromatin 

 bodies but no trace either of the old macronucleus or of the 

 macronuclear anlagen. Four micronuclei are closer together than 

 the other three, indicating that the two groups arise from each 

 of the two original vegetative micronuclei. The scattered posi- 

 tion of the micronuclei indicates the beginning of their degen- 

 eration (see fig. 44, pi. 4) which shows the same feature in a 

 conjugating animal. 



The next change consists in the practically "complete disappear- 

 ance of the old macronuclear membrane and in the degeneration 

 of the so-called reduction micronuclei to the number two (or 

 one). It was not possible to trace the method of degeneration 

 of the micronuclei^ but it is positive that in .the generation which 

 follows the above described stage only one or two are present. 

 Maupas and Hertwig figured the degenerating micronuclei in 

 conjugating animals as homogeneous minute dots the structure 

 of which is not discernible (Hertwig '89, fig. 7, pi. 1; Maupas 

 '89, fig. 13, pi. 12). Hertwig at first could not determine 



