454 LORANDE LOSS WOODRUFF. 



animals not supplied daily with fresh culture fluid than in the 

 regular lines." 



It is apparent then from this experiment that the same general 

 conclusion which was derived from all the previous ones is again 

 justified, viz., the culture conditions may, at most, initially in- 

 fluence the appearance of endomixis; but once established the 

 rhythmic period characteristic of the species is maintained with 

 great exactness, resulting in a remarkable synchronism of the 

 process in the different races. General normal environmental 

 changes obviously do not permanently alter the fundamental 

 inherent rhythmic periods of the organism. 



C. 



A study now can be made of the phenomena under con- 

 sideration in the same races of Paramecium aurelia when bred 

 in a relatively large amount of culture medium supplied fresh 

 daily, and in a relatively small amount of culture medium 

 changed on alternate days. This involves, obviously, the com- 

 parison of the results from the two previous experiments since 

 these were conducted simultaneously and afford the requisite 

 data. Therefore the culture graphs of these two experiments 

 are presented, one above the other, so that identical five-day 

 periods coincide, in Figs. 9, 10, II and 12. 



It is to be noted that As and 05 were branched from A and 

 very soon after endomixis had occurred in the latter cultures; 

 Bs came from B during the actual occurrence of endomixis; 

 while Ms was branched from M toward the end of a rhythm 

 as the subsequent appearance of the process in M at period 60 

 shows. 



The four figures mentioned and the following tabulation of the 

 periods in which endomixis occurred in the various subcultures 

 shows the synchronism of the reorganization process in all the 

 pairs of cultures under the markedly different environmental 

 conditions. It is difficult to say whether this coincidence of the 

 process is more exact between different races under the same 

 culture conditions or between the same races under different 

 culture conditions, because most of the variations are so small 

 that they fall well within the limits of error involved in the 

 five-day plotting method, etc. (cf. p. 440). 



