262 



CHARLES E. BILLS. 



table the values given for the untreated controls are interpolated 

 averages obtained for the six alcohols in a series of experiments 

 elsewhere described (Bills, ig2^b). They were made a few 

 days before the present experiment was performed, during a 

 period of extended constancy in the cultures. Therefore, these 

 values are admissible for comparison here, and are probably more 

 nearly accurate than single observations would have been. 



From Table VII. it is clear that the three-day exposure to i.o 

 per cent, ethyl alcohol increased the susceptibility of the para- 

 mecia to a narcotizing concentration of ethyl alcohol ; and, 

 similarly, to each of the other five alcohols. In other words, 

 paramecia are not acclimatized to ethyl alcohol under the con- 

 ditions of this experiment. Unlike Daniel's spirostoma and 

 stentors which under similar conditions became more resistant to 

 ethyl alcohol, paramecia became more susceptible to all alcohols. 



TABLE VII. 



SHOWING THE EFFECT OF EXPOSURE TO ALCOHOL ON THE ACTION OF 

 ALCOHOLS ON Paramecium. 



I wish to express my appreciation of the interest and guidance 

 given me in the course of these experiments by Professor S. O. 

 Mast and Professor H. S. Jennings; and my thanks to many 

 other persons for their assistance in many ways. 



SUMMARY. 



1. A mixture of B. lactis acrogcnes and B. aquatilis (sp. ?) 

 constitutes the best food found for Paramecium. 



2. When paramecia are exposed to an alcohol .in sufficient 

 strength they are at first incoordinated in movement and then 

 inactivated. Later toxic effects are manifested by marked in- 



