348 University of California PiMicaiions in Zoology [Vol. 20 



In one respect, the experiments were disappointing. Paramaecium 

 did not disintegrate in the manner of planarians and annelid worms. 

 Instead blisters appeared invariably over the posterior contractile 

 vacuole. Sometimes the animals died without further distortion. At 

 other times, the blister grew larger and larger until the ectoplasm 

 was disrupted and the endoplasm flowed out. For this reason, the 

 metabolic rate of the region of the neuromotor center was not 

 determined. 



But it was found that the anterior cilia invariably ceased beating 

 iirst, from five to fifteen seconds earlier than the cilia of the cyto- 

 pharynx and posterior end. The following is a typical experiment. 



EXPERIMENT NUMBER fi 



11:50 A.M. Animal isolated in 6 per cent alcohol to 20 c.e. of which a small 

 drop of 1 per cent methylene blue had been added. 

 11:52 A.M. Circus movements to the left. 



11:56 A.M. Movements slower, slight blister over posterior contractile vacuole. 

 12 M. End over end movements very slow. Blister much larger. 

 12:05 P.M. Anterior cilia cease. 

 8 second.s later. Cytopharyngeal cilia cease. 

 2 seconds later. Posterior cilia cease. 



When 4 per cent alcohol was used, the process often required 

 thirty minutes, but the events were in every case similar to those 

 above described. 



The animals lived in 1 per cent antipyrin about twelve minutes, in 

 %o per cent nicotine about twenty minutes, in 1 per cent morphine 

 hydrochlorate about seventeen minutes, in 1 per cent strychnine about 

 five seconds. Except in the strychnine, which was used too con- 

 centrated, the behavior was similar to that observed in alcohol. 



The experiments show that there is a gradient in Paramaecium 

 of a nature that one would expect if the fibers are conductile in 

 function. 



The experiments certainly do not support Neresheimer's conten- 

 tion that the organisms cannot be narcotized. The movements of 

 Paramaecium are appreciably slowed down in all the narcotics used. 

 In one case an animal remained qiiiet in 4 per cent alcohol for 

 fifteen minutes. On being disturbed, it moved about very slowly, in 

 sharp contrast to the rapid movements of an animal not so treated. 



The behavior of Paramaecium in these solutions of narcotics was 

 found to be not unlike that of annelid worms, except that Para- 

 maecium did not similarlv disintegrate. 



