Researches on the Discharge of the Electric Organ. 7S 



the succeeding discharges. Tlie shutter could be opened as desired, 

 but tlie chscharge curve could not be obtained. So laying a living 

 fish on a wooden board having a hole of the shape of the organ for 

 an electrode, and applying a pair of electrodes to the dorsal and the 

 ventral side of the organ b}^ my hands, the registering drum was 

 rotated. Judging the proper instant, which could be readily 

 known by the behaviour of the fish before its discharge, the shut- 

 ter, used as time-shutter, was opened. When the discharges 

 occurred, which were percei\'ed l)y the shocks felt, the shutter was 

 closed. In the two oscillograms taken under difïerent conditions, 

 we see that a shock always consists of two discharges followed ]jy 

 a very low one, the second discharge being a little smaller than the 

 first. The proper period of the discharges of a living malaptervnis 

 and its variation by the change of the temperature were 

 investigated by Koike ''" with tlie string galvanometer. In his 

 results a shock consists of many periodic discharges, which Garten 

 and Koike thought to be theefïectof rhythmic central excitations. 

 In our experiment, tlie kind of Hsh was difïerent from his, and in 

 his experiment the fish was placed in water whereas ours was 

 placed in air. Therefore it is not strange that the results do not 

 agree in the two experiments. But in the face of our experimental 

 results, perhaps the second and the succeeding discharges would 

 l)e of a secondary nature, for a ^-imilar phenomenon 7. e. two large 

 discharges followed by a very low one was frequently observed in 

 many experiments of the indirect stimulation given to the prepara- 

 tion of the isolated nerve-organ. 



We shall next show two experiments regarding the discharge 

 l»y the stimulating current of long duration in the a^icendiiig or 

 in the descending direction. Oscillograms No. 7(j and No. 77 (Plate 

 XXX.) are two such experiments. These are the results with 

 difïerent preparations. The original object of tliese experiments 

 was to test Hoorweg's considerati(tn that the opening stimulus 

 was the efïect of the polarisation current flowing tlirough the shunt 

 ordinarily used for the regulation of the stimulation current. 

 The result was of course negative. But on examining the 



* Zeitschrift für Biologie, Bd. 51, 1910. 



