Immunity of Lower Organisms to Ethyl Alcohol 6ii 



3 Acclimatization to alcohol is shown not alone in an increase 

 of resistance to a stronger solution but in changes in the behavior 

 of the organisrns. The unacclimatized animal responds to the 

 stronger chemical by powerful motor reactions while the acclim- 

 atized organism shows much slighter activity. 



4 In a weak solution of alcohol (i per cent) the beginning of 

 acclimatization is usually evident within a few hours. This in- 

 creases in a fairly uniform ratio until about the fourth day, at 

 which time a maximum degree of immunity may be expected. 



5 The degree of resistance produced corresponds in a measure 

 to the strength of the alcohol used as an acclimatizing medium. 

 As compared with the resistance produced by a I per cent me- 

 dium that due to ^ per cent is lower in degree. In a medium much 

 stronger than i per cent the correspondence does not hold, since 

 stronger solutions decrease the resistance by producing injury to 

 the organism. 



6 The fact that in these experiments some strains show little 

 or no capacity for becoming acclimatized to alcohol although tried 

 for long periods of time and with refined methods makes it ques- 

 tionable whether acclimatization takes place so readily and to so 

 high a degree as is commonly supposed. 



Dr. Jennings informs me that extensive work in other chemicals 

 carried on under his direction points to the same conclusion that 

 I have just set forth — much of the work having given entirely 

 negative results. 



7 Tolerance, or acclimatization, to ethyl alcohol does not in- 

 crease the resistance of the organisms to other chemicals. On the 

 contrary it usually renders the animals less resistant to other agents. 

 This matter was studied in detail in Stentor and Spirostomum 

 for an acid, an alkali, and for two substances belonging to the 

 group of alcohols, namely, glycerin and methyl alcohol. In all 

 cases the animals which had acquired an increased resistance to 

 ethyl alcohol as a result of living in a I per cent solution showed no 

 increase or an actual decrease of resistance to other chemicals. 

 Thus the immunity produced by ethyl alcohol is specific; it does 

 not produce protection against all chemicals. 





