TOXIC ACTION OF KCN ON PARAMECIUM AND DIDINIUM. 21 7 



time, showing that the results are comparable and real ; that is, 

 that there are actual differences in survival time. This indicates 

 so far as this experiment goes that there is an absolute increase 

 in the survival time of the cells in hay infusion from one division 

 to the next division, rather than that the increase is due to 

 decrease in survival time of their sisters killed immediately after 

 division; for the survival time of the latter tended to remain 

 about the same throughout the experiment as shown by the 

 horizontal trend of curve C. 



TABLE III. 



Paramecium. 



A. Time in minutes between division of Paramecium and the killing of one 

 sister in AT/75 KCN. 



B and C are self explanatory, each number representing an average of thirty 

 individuals. 



D. Average difference in survival time between the paramecia which were killed 

 immediately after dividing and their sisters which were killed at the above intervals 

 after living in native hay infusion. Each number represents the difference between 

 the two preceding numbers in the same column. 



We may then briefly summarize the results from the previous 

 experiments on Paramecium by saying that these have clearly 

 shown that beginning at division there is an increase in the 

 resistance of Paramecium to KCN when it is permitted to live in 

 hay infusion, while if placed in tap water the resistance decreases. 



By using hay infusion it would be practically impossible to 

 show in Paramecium that these results are due to the state of 



