142 



ELECTRICITY AND PROTOPLASM 



[Ch. VI 



the Paramecia aggregated at one pole was determined by the 

 strength of the current, as follows : A current of 3 S caused 

 in general a movement towards the kathode, although many 

 individuals appeared not to be affected by it. In 20 seconds 

 the anode end of the fluid was almost free from Infusoria. 

 With currents of 6 S and 15 S the aggregation at one pole be- 

 came more complete and took place in a short time. Indeed, 

 there was a relation found between the time required for 



5E 



10(5 206 30c! i06 506 60S 



STRENGTHS OF CURRENTS 



70d 



Fig. 34. — Curve showing relation between strength of currents and relative time 

 elapsing hefore Paramecia have aggregated at the kathode. The ordinates are 

 measured by the reciprocals of the number of seconds elapsing ; the abscissee, by 

 the strength of current in 5's. 



aggregation at the kathode and the strength of current 

 employed, which is instructive, and is given above in graphic 

 form (Fig. 34). 



This curve shows that as the current increased from 3 S to 

 21 S the rapidity of aggregation increased, but as the current 

 increased still further this rate diminished until locomotion 

 nearly ceased at above 60 S. The intensity, therefore, of 21 S 

 produced the most rapid movements. 



Upon opening the current, the Infusoria in all cases swim, 



1 ampere per sq. mm. (designated 5), then we must divide Ludloff's galva- 

 nometer readings (given in milliamperes) by x^^ttj oi" (which is the same thing) 

 multiply them by 50. That -will give us the current in S's per sq. mm. All of 

 the numerical data given in the text have undergone this operation. 



