458 



LORANDE LOSS WOODRUFF. 



pronounced, usually bring on endomixis slightly earlier than it 

 would have occurred if the cells had been left in the environment 

 in which they were at the last reorganization period. But 

 after this initial change the periodicity characteristic of the 

 organism is resumed and persists. 



In addition, however, this experiment suggests another point 

 of interest: the length of the rhythm is apparently partially 



FIG. 12. 



independent of the number of cell divisions the periodicity 

 being one in which time, so to speak, is an important factor. 

 This is a most surprising result, because such profound reorgani- 

 zation phenomena as are involved in endomixis must bear a 

 more or less definite relation to the physiological activity of 

 the protoplasm, the best criterion of which is generally considered 

 to be growth and reproduction as indicated by the division rate. 

 More experiments obviously are needed to resolve this 'time 

 factor ' into its significant elements. 



EXPERIMENTS SERIES III. 



Peebles states that Horlick's Malted Milk is a most satis- 

 factory culture medium for Paramecium if used in a .2 per cent. 



