EFFECT OF EXCRETION PRODUCTS OF PARAMAECIUM 573 



3r 



Fig. 5 Record of the experiments on the effects of changing the culture medium 

 at twenty-four-hour intervals and at forty-eight-hour intervals, when Paramae- 

 cium aurelia is bred in /wo drops of hay infusion. The ordinates represent the aver- 

 age daily rate of division of the four lines of organisms, again averaged for four 



day periods. Medium changed at twenty-four-hour intervals = ; changed at 



forty-eight-hour intervals = . 



Fig. 6 Record of experiments on the effect of changing the culture medium at 

 twenty-four-hour intervals and at forty-eight-hour intervals, when Paramaecium 

 aurelia is bred in jive drops of hay infusion. The ordinates represent the average 

 daily rate of division of the four lines of organisms, again averaged for four day 



periods. Medium changed at twenty-four-hour intervals = ; changed at 



forty-eight-hour intervals = . 



THE JOURNAL OF E XPEBIMENTAL ZOOLOGY, VOL. 10, NO. 4 



