NUCLEO-CYTOPLASMIC RELATION OF OXYTRICHA 



13 



IV. CELL SIZE AND NUCLEAR SIZE 



In order to analyze the data accurately four parts of the life of 

 the race were selected, designated respectively A, B, C, and D, 

 each of which comprises, as it were, a different phase of the repro- 

 ductive activity. Part A includes cells in which the rate of 

 reproduction and general vitality is very low (less than one di- 

 vision in twenty-four hours) ; part B includes cells in which the 

 reproductive activity is actually and relatively very, high (aver- 

 age about three divisions in twenty-four hours) ; part C includes 

 cells in which the reproductive activity is about 'normal', though 

 considerably less than B (average about two divisions in twenty- 

 four hours) ; and part D includes cells which have again reached 

 a stage of marked morphological and physiological degeneration. 



The data may be considered best in connection with the tables. 

 Table 1 gives, for each of the twenty-one ten-day periods for 



TABLE 1 



