490 Journal of Co)iiparative Neurology and Psychology. 



(1903 a, p. 92) determined this by direct observation of the 

 ciHa on animals in viscous media of various sorts, inventing a 

 number of new media for this purpose. My own results were 

 obtained by observation of the currents produced by the cilia. 

 These observations were made by the use of India ink in the 

 water containing the animals, as set forth above (p. 442); they 

 add certain features to the results set forth by Statkewitsch. 



/^t^. ij. Currents of water produced by the action of llie cilia in tlie reac- 

 tion of Paramecium to tlie electric current, a, electric current weak, water cur- 

 rents reversed only at the anterior tip — most markedly in the oral groove ; i, 

 electric current strong The arrows show the direction of the water currents. 



With a weak electric current the ciliary currents, after ori- 

 entation is reached, are everywhere backward. At the very 

 anterior tip (directed to the cathode) the currents are perhaps a 

 little less strongly backward than when the animal is not sub- 

 jected to electricity. This agrees with the results of Ludloff 

 and of Statkewitsch (1903 a), who found that in a weak cur- 



