456 LORANDE LOSS WOODRUFF AND RH. ERDMANN 



assumed its typical macronuclear characteristics. The elongated 

 form is the prevailing one in the interval between two cell divi- 

 sions, the broad axis is relatively short, while the few granules 

 within the membrane are small. The appearance of an old and 

 new macronucleus is markedly different and the two stages can- 

 not be confused (compare figs. 3, 4 and 5, pi. 1, with figs. 28, 

 29 and 30, pi. 3). Figure 29 and figure 30 (pi. 3) show the new 

 macronuclei. The animal portrayed in the former is from the 

 above-mentioned Line VI in the 4187th generation. One large 

 and two small chromatin bodies are visible. The latter shows 

 a cell which was taken from the main culture in the 1201st gen- 

 eration. The staining capacity of the macronucleus is very 

 marked; the micronuclei present no unusual features; and two 

 chromatin bodies still persist. A dividing animal from the main 

 culture at the 1432d to 1433d generations (fig. 28, pi. 3) further 

 illustrates the distribution of the chromatin bodies. This aninlal 

 has undergone four divisions during the previous twenty-four hours 

 and is now just completing the fifth cell division, while the micro- 

 nuclei have divided precociously for a sixth cell division. This 

 affords another example of the acceleration of the division rate 

 which is characteristic of the ascending phase of the process. 



The ensuing divisions in the rhythmical period efface the last 

 trace of the chromatin bodies and, therefore, of the reorganiza- 

 tion process. In conjugation, as has been shown by Maupas 

 and Hertwig, the chromatin bodies undergo the same fate at the 

 same time. The reorganization of the cell is completed. 



In the description of the process nearly all the examples pre- 

 sented have been animals from Sub-culture IE (4020th to 4359th 

 generation) bred for this particular purpose under constant en- 

 vironmental conditions. As already described in the section on 

 technic, animals had been preserved at irregular intervals through- 

 out the first six years of the life of the main Culture I and on the 

 basis of these it was early stated ('08) that profound nuclear 

 changes occur which cannot be interpreted as abnormal and 

 which demand further study. The character and significance 

 of these changes obviously could only be determined by such 

 an intensive daily study of all the available animals as the pres- 



