Rosearches on the Discharge of the Electric Organ. 5 



advantageous, for the investigation of the discharge curve, to 

 stimulate the organ not through the nerve^trunk but directly, 

 so that each plate may receive the stimulus at the same instant. 

 For the direct stimulation of the muscle, it is customary to use 

 curara in order to l)enuml> the nerve-endings. In the case of 

 the electric organs, however, there is known no such drug that 

 can be used witli the same effect. Hence the term direct stimula- 

 tion used in tins paper in relation to the electric organ has a some- 

 what different meaning from that used in the case of a muscle. 

 Tiiough the stimulating electric current is sent directly through 

 the electric organ, tlie stimulus is probably in the main imparted 

 to it through the nerve-fibi-es distributed in it. Nevertheless, in 

 that way the condition of simultaneous stimulation can be better 

 fulfilled tlinn when tiie stimulation is given through the nerve- 

 trunk. ^L)reover. when the nerve-trunk is left attached to the 

 organ, the discharge cui'rent flowing through the nerve-trunk iè 

 very lial;)le to act as a second stimulus and to cause a secondary 

 discharge of considerable magnitude, by which a tertiary discharge 

 is called forth, and so on. This makes the phenomenon very 

 complex. But. in tlie case of direct stimulation of the organ, if 

 the nerve-trunk be carefully taken away from the organ, and if its 

 temperature l)e kei)t sufficiently low, there Avill result only a very 

 Aveak secondary discharge (Plate 1., Fig. 2). In accordance with 

 these considerations, we empk\ved direct stimulus in general, ex- 

 cept when the [)i-operty of the nerve was to be investigated. In 

 the former case the ti\e trunks of the nerves .were cut off as near 

 as possible to the (jrgan. and the whole or a part of it was utilised. 

 In the latter case, when the stimulus was to be sent through thé 

 nerve-trunk, al)Out a quarter of the organ with one nerve-trunk 

 was employed. 



