86 LORANDE LOSS WOODRUFF, 



1/500 alcohol to 4 parts of hay) the effect is a continued stimulus 

 which sustains the high rate of division even during periods of 

 depression of the control series." " There is no doubt that for 

 a time at least, alcohol will prevent death during periods of de- 

 pression. ..." "... there is evidence that . . . the general vi- 

 tality would decrease under the constant stimulus as it does under 

 treatment with hay infusion alone, although much more slowly." 

 " Notwithstanding the more rapid living, the general vitality does 

 not seem to be affected badly by the alcohol." It was chiefly to 

 determine the latter point that this investigation was begun, and 

 I shall outline the progress of the work to the present time. 



II. Methods. 



I chose Paranicciiiui aurelia ^ for the main line of experiments 

 chiefly because considerable work has already been performed on 

 this organism ; and because it is one of the more generalized of 

 the ciliates ; and lastly because its cosmopolitan distribution ren- 

 ders it a convenient form to be studied in all laboratories. It 

 seems to me to be more desirable, in the present state of our 

 knowledge, to learn one form thoroughly, if that is possible, 

 rather than to distribute our energies over a broader field. As a 

 subsidiary line, for comparison and as a check on the Paramecimn 

 cultures, I employed a culture of Stylonydiia mytilus. 



The general method of carrying the cultures is identical with 

 that which has been described in detail in an earlier paper," so 

 that a brief outline at this time will suffice. 



A "wild" individual was captured and placed on a depression 

 slide in five drops of hay infusion. This infusion was made by 

 putting about three grams of hay or grass in 200 c.c. of tap water 

 and then raising the temperature to the boiling point. This in- 

 fusion was generally used as soon as it had again attained the 

 room temperature. It was made fresh daily as a rule. Sufficient 

 bacteria developed to provide ample nourishment for the infusoria, 

 and since all precautions were taken in selection of the hay, etc., 



' The specific name aurelia, instead of caudatum, is adopted in accordance with 

 the data advanced by Calkins, " Paramecium aurelia and Paramecium caudal um,^'' 

 Biol. Stud. Pupils of W. T. Sedgwick, Chicago, 1906. 



' Lorande Loss Woodruff, •' An Experimental Study on the Life-History of Hypo- 

 trichous Infusoria.,^' yournal 0/ Experimental Zoology, IL, 4, I905. 



