GROWTH 



521 



A year later Popoff (1908) measured the growth of P. caudatum by 

 killing a sister cell immediately and the other member of the pair at a 

 given time after fission. His results are expressed in micrometer units 

 which have been converted into microns. The average of the cells killed 



1 r 



—280 



O 



100 1| z 



^^ 



HOURS 



u 



4 6 8 



_i I 1 I I I I I l_ 



25 000 

 20000 



< 



15000 



3000 



/ / 



\A I8| 24-1 



Figure 130. Growth in length and in area of Paramecium caudatum. Data: M from 

 Mizuno (1927), S from Schmalhausen and Synagajewska (1925), E28 and E38 from 

 Estabrook (1910), J from Jennings 1908), and P from Popoff (1909). 



at fission was taken as the standard size at zero time, and the average 

 differences for the intervals were added successively to obtain the data 

 plotted in Figures 130, 131, and 132. He measured length (L), breadth 

 (B), and thickness (T) and computed the volume as = 47cLBT/24, 

 assuming the form to be ellipsoid, and he also gives similar measure- 

 ments of the growth of the nucleus and of the nucleocytoplasmic ratio. 

 Estabrook (1910) investigated the effect of various chemicals on the 



