6o6 y. Frank Daniel 



Whether animals acclimatized to weak concentrations of alco- 

 hol have gained a benefit which will help them when tested to a 

 fatal dose of a substance kindred to alcohol is a question of closer 

 interest. We shall first study this in one of the lower alcohols. 



D The Action of Glycerin C,H, (OH)^ 

 I General Effects 



Normal unacclimatized Stentors. Subjected to a molecular 

 concentration of glycerin (f) the animals remained motionless 

 for an instant, then suddenly began backing and contracting 

 rapidly. Membranellae became non-functional, usually within 

 45 seconds. The peristome (membranellae) was soon lost. Signs 

 of plasmolysis — especially m the posterior part of the body — fol- 

 lowed. The color was retained to a marked degree. Long after 

 the membranellae had stopped beating the body cilia continued in 

 activity (the opposite effect from that of ethyl alcohol). 



Stentors acclimatized in I per cent alcohol. In the same con- 

 centration of glycerine these gave reactions which could not be 

 distinguished from those described above. 



A single peculiarity in acclimatized animals may be mentioned. 

 In a number of cases these assumed a characteristic pipe-shaped 

 appearance, similar to that seen when normal Stentors were kept 

 in water of very great purity. 



The most characteristic phenomenon observed from the action 

 of glycerin was the loss of the peristome or membranellae. This 

 was noted alike in acclimatized and unacclimatized animals and 

 in solutions varying in concentration from a molecular solution to 

 a concentration of one-fourth molecular strength. 



The first signs of injury to the organism came as a stoppage 

 of these peristomal cilia. The peristome then became detached 

 in a ribbon-like fashion and either hung from a point of attachment 

 or, as was more usual, was entirely lost. 



A phenomenon of great interest was the regeneration of the 

 peristome after its loss in the manner just described. In a sub- 

 lethal concentration those animals which gave off the peristome 

 in the afternoon had by the following morning regenerated a new 

 one. 



