578 



THE PHYSIOLOGY OF ELECTRICAL ORGANS. 



Oh 



x 



- •-— — t----i — i — t — t 



01 02 05 o^ oz>" 06 



the change is thus strictly monophasic. This is well shown by the 

 character of the single excursion of the mercurial meniscus of the 

 capillary electrometer, produced by a single response of the excised organ 

 of Malapterurus, when in a low state of excitability. An examination of 

 this excursion, as photographed (see Fig. 294, A), shows that, after the 

 application of the stimulus at the time (x), a period of delay occurs 



succeeded by a rapid rise, due 

 to the development of the 

 change ; the subsidence is far 

 more gradual, and shows no 

 evidence of any counter elec- 

 tromotive effect bringing the 

 meniscus back to the initial 

 position, such movement as 

 exists being largely the dis- 

 charge of the charged capil- 

 lary through the short cir- 

 cuiting shunt. The character 

 of the excursion may be con- 

 trasted with that of B in the 

 same figure (Fig. 294), where a 

 counter-effect exists. This 

 was obtained in the following 

 way. The preparation was 

 connected with one pair of 

 condenser - plates, a second 

 pair of plates at 3 mm. dis- 

 tance being connected with 

 the capillary electrometer. 

 With this arrangement, both 

 the development and the 

 cessation of a monophasic 

 change should produce an 

 electromotive disturbance in 

 the condenser plates, the 

 former causing a change of 



02" 07>" 01*" '03 



JV 



01 — 1 — 1— -1 



— H 01" -02" 03" 



Fig. 294. — Outlines of records obtained by photo- 

 graphing the capillary electrometer. A, Mal- 

 apterurus organ strip of low excitability ; 

 electrometer connected with caudal and 

 cephalic ends of strip, with short circuiting 

 shunt of 80 ohms. Temperature of strip 

 = 5° C. The nerve was excited by a single 

 induced current at the moment marked x. 

 The single monophasic response commences at 



- 01 sec. and is fully developed by '02 sec. B, 



Same strip as that used in A, but connected One Sign, the latter one Ot the 



with a pair of condenser plates ; the electro- opposite sign. If a 1110110- 



meter was connected with another set of plates -pha sic chano'e occurs in the 



at 3 mm. distance. The change in the organ " ° ,. J ., u ,-, 



commences at 0-01 sec. after the excitation organ preparation, it Should 



of the nerve producing a condenser charge ; it produce a diphasic effect in 



ceases at 0-016 sec, producing a discharge _ of the con d ensers connected With 



opposite sign. Temperature of organ strip, „ ... ^i , , 



5°C. Condenser 537 C.G.S. units. C, Same the capillary. Ihe photo- 



as B, but temperature of strip 30° C. Time of graphed records of the elec- 



commencement of response after excitation of j. compter excursion outlined 



nerve, 0*006 sec. ; cessationlof response indicated . ™ _-T. . , ' <, » ,•,. 



by discharge of opposite sign at "008 sec. m B, V lg. 294, IS clearly Ol this 



diphasic character, the sudden 

 rise being succeeded by a sudden fall, which brings back the level of 

 the meniscus. The records A and B are both those due to responses 

 of the organ at a low temperature ; in 0, Fig. 294, the record obtained 

 from the same organ at 30° C. shows that the response culminates 

 in YJT5-& sec. after its commencement. 1 



1 Gotch and Burch, loc. cit. 



