90 LORANDE LOSS WOODRUFF. 



IV. General Effect of Alcohol on the Division Rate of 

 Paramecium and Stylonychia. 



(rt) Parainecium. 



On July 19, 1907, a second culture of Parajneciuvi was 

 started by isolation of an individual from each line of culture I. 

 This second culture, designated Paramecijim V , was carried under 

 identically the same conditions as culture I, being subjected to 

 the same temperature changes, etc., and given the same culture 

 medium at the same time, except that instead of each individual 

 receiving five drops of hay infusion (as in the case of culture I, 

 the control), each received four drops of hay infusion and one 

 drop of 1/500 alcohol. There were, then, two cultures each 

 consisting of four lines which had been under observation for two 

 and one half months. The only apparent difference in the con- 

 ditions of the two cultures was that one was subjected to one part 

 of alcohol to 2,500 parts of culture medium.^ 



The effect of the alcohol was seen in a slightly increased rate 



of division of culture V (see Fig. i, line) above that of the 



control during the first five-day period. But after that, during 

 the remaining twenty-five days of the experiment, the alcohol 

 caused a decrease in the division rate. This culture was discon- 

 tinued on August 19, 1907. In Table I is given the actual daily 

 record of generations of the control culture and of the alcohol- 

 ized culture, as an illustration of the general method of keeping 

 the records of all the cultures throughout the work. 



On November 6, 1907, another culture (P) was started by 

 isolation from culture I and given the same treatment as that to 



which culture P was subjected. A glance at Fig. 2 ( line) 



shows, however, that the effect of alcohol was this time a stimu- 

 lation of the rate of division, for during the first thirty days of 

 the experiment the rate was considerably more rapid than that 

 of the control. 



There is then, comparing the results of culture V and those 

 of the first thirty days of culture I", a clear-cut example of a 

 stimulus (alcohol) causing a general retardation of the division 



^ Various amounts of alcohol were tried and the strength here employed was chosen 

 as the one giving the best result. All strengths of alcohol which were tried at this 

 period produced the same general effect. 



