5o6 Journal of Comparative Neurology and Psychology. 



dence thus far brought forth, that the phenomena observed in 

 acid solutions, as described by Greeley (1903), have any spe- 

 cial significance for the theory of electrotaxis, such as that au- 

 thor assumes. The known facts point to the following general 

 statement of the phenomena. Immersion in chemicals, of vari- 

 ous characters, causes the organism to swim backward. If at 

 this time the Paramecia are subjected to the electric current, 

 they continue to swim backward, and, becoming oriented, there- 

 fore pass to the anode. This movement to the anode ceases as 

 soon as the stimulating action of the chemical ceases. 



In order to make out a case for the theory advanced by 

 Greeley, it will be necessary to show clearly that this general 

 statement is incorrect.' 



IV. Present Position of Investigation of the Behavior 

 OF Paramecium. 



I believe it may be said that we are now able to make a 

 general, qualitative survey of the chief facts and factors in the 

 behavior of this representative of the unicellular animals. There 

 are doubtless still some dark points ; the reaction to the electric 

 current, for example, is still hard to place in the general scheme 

 of behavior, though recent researches have gone far toward 

 clearing up this matter. But it is true that we know, in a 

 general way, most of the chief methods of action of this ani- 

 mal, and the way in which these are affected by the chief classes 

 of external conditions. There still remains the investigation of 

 the intimate physiological processes underlying the gross fea- 

 tures of the reactions, and especially the quantitative study of 

 the phenomena which the qualitative examination has brought 

 out. Our present knowledge, then, amounts to a preliminary 

 survey, showing us in the gross the phenomena which require 

 investigation in detail. Attempted quantitative study of 

 phenomena of which the qualitative, purely descriptive, features 



' Sine- the above was written, Greeley's final paper has appeared (Biol. 

 Bull., Vol. 7, pp. 3-32). It raises many interesting questions, which I hope to 

 touch upan later. (Note added during correction of proof.) 



