124 Regulation of Size in Unicellular Organisms 



Rate of change of size. How long does it take to 

 accomplish such a change of size, and how permanent 

 is the change? PopofI and Rautmann, on the basis of 



120 



10 15 20 ZS 



Temperature in °C 



30 



Figure 37. Combined effects of age of culture, hunger, and temperature, 

 upon the mean body volumes of Stentor coeruleus. The sizes when in a 

 flourishing culture at 15° to 22° were taken as 100 per cent, and the measure- 

 ments shown were made after 3 to 7 days standing at one of the three 

 temperatures indicated. (Data of Allescher, '12). 



a very few observations, concluded that the change of 

 size was completed in about the space of time required 

 for one whole generation of the organisms to grow up. 



