EFFECTS OF LOWER ALCOHOLS ON PARAMECIUM. 261 



The Question of the Adaptation of Parmecium to Alcohol 

 How does a preliminary exposure of Paramecium to a low con- 

 centration of ethyl alcohol affect the subsequent resistance to 

 a stronger dose of ethyl alcohol, and of its homologues ? 



Towle (1904), working with electrolytes and simple organic 

 compounds, concluded that " paramecia become readily habitu- 

 ated to solutions in strengths which are not soon fatal." Daniel 

 (1908) found that paramecia when transferred gradually into 

 distilled water become adjusted to this otherwise deadly sub- 

 stance. Estabrook (1910) developed in Paramecium a tempora- 

 rily increased tolerance for strong doses of sodium chloride. 

 Neuschlosz (ic>2ia) found that Paramecium can develop a high 

 resistance to dyes of the thiazin, benzidin, and triphenylmethane 

 series. Neuschlosz later (iQ2ib) reported that paramecia ac- 

 climatized to trivalent arsenic are at the same time resistant to 

 trivalent antimony. Woodruff (1908) observed that alcoholized 

 paramecia become more sensitive to copper sulphate. Their 

 behavior toward a stronger dose of alcohol was not recorded. 

 A case of adaptation in Spirostomum and Stentor reported by 

 Daniel (1909) is of special interest, inasmuch as the method 

 . of experimentation is essentially identical with my method on 

 Paramecium; the results, however, being different from mine. 

 Daniel claims that he sometimes produced in these protozoa a 

 slight adaptation to ethyl alcohol, but that this was accompanied 

 by an increased susceptibility to methyl alcohol. 



My experiments were made as follows: To 10 cc. of the 

 Clone 10 culture taken from near the surface 10 cc. of 2.0 per 

 cent, ethyl alcohol was added, making a i.o per cent, solution of 

 alcohol. This mixture was put into a 30 cc. Stender dish and 

 kept at approximately 24 for three days. At the end of this 

 period the paramecia were observed to be distributed thruout 

 the medium, appearing healthy, and distinctly more active than 

 the controls altho possibly somewhat thinner. They were then 

 exposed for one hour to each of the six alcohols in the concentra- 

 tions indicated in Table VII., using quantities large enough to 

 eliminate practically all error resulting from the presence of 

 the original ethyl alcohol (see Bills, 19230). 



The results obtained are presented in Table VII. In this 



