134 Regulation of Size in Unicellular Organisms 



teenth the body volume of their progenitors. There 

 was no indication that any reproduction occurred dur- 

 ing the starvation period, so that probably the original 

 individuals gradually lost bulk. Mean body volume 

 appears to have diminished progressively in a logarith- 

 mic sort of way. This might be taken to mean that the 



2 4 8 16 32 



Concentration of food 



Figure 41. Effects of concentration of Chlorogonium as food upon Col- 

 poda. In the lower curves are indicated the fates of the various individuals ; 

 in the upper two curves are the body sizes and the durations of life from 

 hatching to division-encystment. The two body sizes shown at the relative 

 concentration 1 are of permanent cysts which were formed at the end of 

 18 hours ; all other sizes are of division cysts which gave quadruplet progeny. 

 (From Adolph, '29). 



expenditure of bodily substance for energy was pro- 

 portional to the amount of body left to expend it. Stu- 

 dents are constantly surprised by the endurance non- 

 encysting ciliates show under conditions of hunger. 



