STRUCTURE OF PROTOPLASM OF PARAMCECIUM. 2/ 



In several instances, after a prolonged exposure to a medium 

 which had been acidulated by the addition of hydrochloric or 

 acetic acid, the paramcecia exhibit still another form of reaction. 

 In these cases the paramcecia orient themselves transversely or 

 slightly obliquely to the direction of the current, and swim very 

 slowly from side to side of the preparation. At the same time, 

 however, the organisms appear to drift passively toward the 

 anode. I observed this form of reaction only about half a dozen 

 times, but on each occasion the reaction was exceedingly well 

 marked. A reversal of the current caused an instant reversal, of 

 both the direction of the swimming and the passive drifting of the 

 organisms. Notwithstanding the peculiar orientation of the para- 

 mcecia, they all tended to form a gathering about the anode 

 under these acid conditions. 



It has been observed by Loeb, Jennings and others that the 

 addition of other substances > like NaCl, to the solution contain- 

 ing the paramcecia will cause a reverse movement toward the 

 anode. I investigated this question and found that the addition 

 of almost any salt in sufficient quantities to extract water from 

 the protoplasm will cause a more or less complete reversal. A 

 large number of salts, of both positive and negative electrical 

 conditions, were used, and the effect was seen to be purely 

 osmotic in character, except in the case of the salts with trivalent 

 anions or cathions. The former, as the phosphates and citrates, 

 act like the hydrates in very weak solutions and completely 

 destroy all traces of a response toward the anode. The latter, 

 as A1 2 C1 6 , produces an almost instant coagulation of the proto- 

 plasm and hence bring about the same effect as the extraction of 

 water osmotically. It has been already stated that a lowering of 

 the temperature coagulates the protoplasm, and it is interesting 

 to note, that a partial reversion of the electrical response may be 

 produced by this means also. After the paramcecia have been 

 exposed to a temperature of 2 to 3 C, for one hour or more, 

 the normal response is entirely lost, and a slight movement 

 toward the anode can be detected. 



Our ignorance of the precise nature of the ciliary response is 

 too great to allow even an attempt at an explanation of the 

 mechanism of this response to the electrical current. We will 



