Table 1. --Minimum total peak current for electrotactic response of aholehole 

 at various "on-fractions" and frequencies 



"good") was obtained in 2 out of 10 experiments 

 (20 percent) at 5 c,p, s,, in 9 out of 15 experi- 

 ments (60 percent) at 10 c,p. s., and in 2 out of 

 7 experiments (29 percent) at 15 c.p. s. It was 

 decided, therefore, that 10 c,p, s, was closer 

 to the optimum frequency than 15 c,p, s. as de- 

 termined by Morgan (1953). The first series of 

 tests also indicated that a greater total peak 

 current was required for satisfactory response 

 at the smaller on-fractions. 



The term "total peak current" is used 

 rather frequently in the discussion that follows. 

 By "total" is meant the total current flowing 

 through the water between the electrodes, as 

 distinguished from the current density. Table 5 

 converts total current to current density and 

 electric field intensity. By "peak" is meant the 

 value of the current at the peak of the pulse as 



distinguished from some sort o f an average 

 current. 



The above conclusions are tentative as it 

 was exceedingly difficult to appraise the response 

 in this quasi-quantitative manner and as it was 

 necessary to utilize the sanne fish several times, 

 thus introducing a "fatigue" factor. It seenns 

 likely that this fatigue factor increased the cur- 

 rent necessary to elicit satisfactory response. 

 Sometimes a fatigued fish would turn on its side 

 in a state of electronarcosis when a current was 

 applied which would otherwise induce electr otaxis 

 in a fresh fish, 



A second series of tests was designed to 

 determine the minimum total peak current for 

 satisfactory response at a constant frequency of 

 10 c.p. s. at each of the following on-fractions: 



