452 



LORANDE LOSS WOODRtTFF. 



ment is essentially a repetition of experiment A of Series I 

 (cf. p. 443) since three races (A, and B) and the character and 

 amount of culture medium are the same as employed before. 

 The results, therefore, now will be analyzed from the viewpoint 

 of Series I. and later from that of the present series. 



The results are shown graphically in Fig. 7 from which it is 

 evident that: 



A study of this table and the graphs which it summarizes 

 shows again practically the same periodicity of endomixis in 

 diverse races on the varied culture medium as was observed 

 in experiment A of Series I. The synchronism is not quite as 

 exact as in the former experiment but, considering all the un- 

 known and uncontrollable variables in such a long experiment, 

 it clearly offers further support for the conclusion that rhythms 

 and endomixis are essentially independent of environmental 

 conditions, and that the culture conditions merely influence 

 initially, if at all, the appearance of endomixis, and that once 

 established the rhythmic period characteristic of the species is 

 maintained within rather narrow limits. 



B. 



This set of experiments involves a study of the periodicity of 

 rhythms and endomixis in different races of Paramecium aurelia 

 when bred in a relatively small amount of culture medium 

 changed on alternate days. The cultures used, as already stated, 

 were As, Os, Bs and Ms and their behavior with respect to the 

 process under consideration is given in Fig. 8. A study of this 

 graph shows that endomixis was observed in : 



1 The animals were not studied cytologically during this period. 



