PLATE 1 



EXPLANATION OF FIGURES 



Descending Phase 



1 Main Culture I, Line b, 424th generation, April 11, 1908. Normal animal 

 in the period when the reorganization process is not in progress. 



2 Subculture IE, Line VI, 4020th generation, October 27, 1913. Normal ani- 

 mal in the period when the reorganization process is not in progress. 



3 Subculture IE, Line Vlh, 4236th generation, February 21, 1914. Animal 

 just before the beginning of the process in the 4238th generation. Macronucleus 

 with coarse granules; two micronuclei which have shifted from their ordinary 

 position close together at one side of the macronucleus. 



4 Subculture IE, Line IV, 4044th generation, November 10, 1913. Small 

 projections from the macronucleus; two resting micronuclei, and several vacuoles 

 containing bacteria. 



5 Subculture IE, Line VI, 4094th generation, December 9, 1913. Large pro- 

 jections from the macronucleus, which is coarsely granular. Two micronuclei 

 shifted from their typical position. 



6 Main culture I, Line c, 452d generation, April 30, 1908. Two chromatin 

 bodies which have been ejected from the partially membranous macronucleus; 

 two micronuclei shifted from their typical position. 



7 Subculture IE, Line VI, 4182d generation, January 24, 1914. Animal in 

 process of division during the descending phase of the process. One chromatin 

 body, numerous vacuoles, four division micronuclei and the remnant of a divi- 

 sion spindle. 



8 Subculture IE, Line V, 4023d generation, October 30, 1913. Several chro- 

 matin bodies, some within and some which have passed out from the macronucleus. 

 Two isolated micronuclei showing indications of division. 



9 Subculture IE, Line II, 4069th generation, December 2, 1913. Macronucleus 

 still further resolved into chromatin bodies; micronuclei are obscured by the 

 macronucleus. Numerous vacuoles present. 



10 Subculture IE, Line VI, 4130th generation, December 25, 1913. Numerous 

 chromatin bodies the position of which in the cell indicates the effect of cyto- 

 plasmic currents. Macronucleus partially membranous. Animal started to effect 

 the process which however was actually accomplished in this line in the 4140th 

 generation. One micronucleus visible. 



11 Subculture IE, Line Ilia, 4271st generation, March 12, 1914. Almost 

 completely disintegrated macronucleus. Two micronuclei dividing to form four 

 'reduction' micronuclei; an irregular division in a third micronucleus. 



12 Subculture IE, Line VIj, 4314th generation, April 4, 1914. Macronucleus 

 nearly devoid of chromatin ; numerous chromatin bodies ; three micronuclei divid- 

 ing to form six 'reduction' micronuclei. 



13 Culture B, Berlin race, October 6, 1913 (see page 473). Numerous chro- 

 matin bodies; six so-called reduction micronuclei. Climax of process. 



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