Protozoan Studies 



VZ 



and his students that the rate of division may be increased by 

 various changes in the chemical composition of the medium. To 

 ehminate error from this source I was careful to have the medium 

 of the centrifuged individuals and the control exactly the same. 

 In the table below, the divisions of three individuals centrifuged 

 24 hours {71-r = 585 X 10*') are compared with the divisions of 

 three control individuals. Both daughters of the first division 

 of No. I were kept, and one of them designated as la. In all other 

 cases one daughter of each division was thrown away. 



In the three series from the centrifuge (not counting la) there 

 were 15 divisions in 23 days whereas in the check there were only 6 

 divisions in that time and two of the series had run out. 



In the table below three individuals centrifuged 32 hours at the 

 same rate are compared with three in the check: 



