Immunity of Lower Organisms to Ethyl Alcohol 603 



Both for Stentor and Spirostomum not only was there no increase 

 In resistance of acclimated animals when tested to hydrochloric 

 acid but there was — especially in Stentor — a clear and unmistak- 

 able weakening. Animals which normally resisted -^^-^ HCl for 

 249 seconds, if first accustomed to alcohol, showed an average 

 endurance of only 78.5 seconds. Spirostomum, while showing 

 less injury, in no case showed advantage by first being acclimatized 

 to alcohol. 



For Spirostomum it will be noticed that a much lower suscepti- 

 bility to HCl was shown. Although its controls were tested in a 

 medium eight times as concentrated as that used for Stentor, they 

 gave a resistance period almost as long as did normal animals 

 of Stentor; while its acclimatized animals were much more resist- 

 ant to this solution than were similar acclimatized Stentors in the 

 much weaker solution. 



This lack of susceptibiHty to acid on the part of Spirostomum 

 has in large part its explanation in the contour of the cell. In 

 Stentor it was seen that in the formation of the coagulum the large 

 rounded mass of endoplasm was drawn away from the pellicula, 

 and that this separation is what causes the cessation of ciliary 

 movement. In Spirostomum, however, the mass of endoplasm is 

 long and columnar and forms into a coagulum more slowly and 

 with a much less destructive eff^ect. The coagulum in passing 

 along the body becomes shorter and thicker. This rounding 

 together with slight constrictions in the cell wall impedes its course, 

 thus allowing the posterior cilia to continue beating often for long 

 periods of time. 



Thus we see that while the formation of a coagulum is destruc- 

 tive to Stentor, the same process gives advantages to Spirostomum 

 when tested to a fatal percentage of hydrochloric acid. 



C The Action of Sodium Hydroxide (NaOH) 



I General Effects 



Normal unacclimatized Stentors in a solution of y^^^ NaOH gave 

 the following characteristic reactions: Slight movement for a 

 brief time (15 seconds) followed by a loss of the membranellae 



