598 



y. Fratik Daniel 



a better increase was shown at the end of the first day than is here 

 given on the second. Probably the most typical results for the 

 series are those on the fifth day. On the seventh a slightly higher 

 average obtains for A, but C is less resistant. Had it been typical, 

 however, there would still be a ratio slightly above two to one. 



Another point may be noted in passing. The control animals, 

 unlike those of Stentor, instead of increasing in resistance, showed 

 a gradual decrease. 



A further study was made in Spirostomum of the immunity 

 shown at considerably later periods of time. 



The greatest difficulty encountered was in keeping the acclim- 

 atizing medium A at its usual strength. In order to do this two 

 plans were tried. In one the culture was changed every few days; 

 in the other it was kept in ground glass vessels which were sealed 

 and set at constant temperature until the time of experiment. 

 The latter method was adopted as giving better results. 



An experiment under these conditions follows in which the 

 organisms were tested after eleven days in the acclimatizing and 

 control media. 



Experiment XI F 



RESISTANCE OF SPIROSTOMUM TO 8 PER CENT ALCOHOL, AFTER LIVIN'G II DAYS IN I PER CENT ALCOHOL 



C Control 



Exp. 



A II Days in I Per Cent Alcohol 



Seconds 



1 cil; 



2 cil] 



3 ci 



4 c: 



5 cil: 



6 ci 



7 c: 



9 ci 

 10 c 



a stop 190 



a stop 50 



a Stop 85 



a stop 95 



a stop 95 



a stop 390 



a stop 45 



a stop 285 



a stop 150 



a stop 70 



Seconds 

 Exp. I cilia stop 30 



2 cilia stop 70 



3 cilia stop 25 



4 cilia stop 160 



5 cilia stop 120 



6 cilia stop 30 



7 cilia stop 65 



8 cilia stop 60 



9 cilia stop 50 



10 cilia stop 30 



H5-5 



64 



We see from this that although the resistance of the control was 

 low, the acclimatized animals have retained their immunity for 

 this period of time. 



