28 Messrs. F. Gotch and G. J. Burch. 



(c.) The capillary electrometer, a large number (about 250) photo- 

 graphic records being taken of the movements of the meniscus. 

 Facsimile reproductions of typical records are given in the fuller 

 communication. The electrometer was used either shunted by a 

 resistance of from 80 to 100 ohms, or in connection with the outer 

 plates of a special condenser, the inner plates of which were con- 

 nected with the fish or its electrical organ. 



The organ responded to mechanical or electrical excitation of its 

 nerves after removal from the fish, the response being unaffected by 

 1 per cent curare, or 1 per cent, atropine solution. No response 

 could be evoked by such chemical agents as sodium chloride, gly- 

 cerine, or weak acid, when applied either to the organ or its efferent 

 nerve. 



The conclusions drawn by the authors from the experiments on the 

 isolated organ and on the entire uninjured fish may be summarised as 

 follows : 



(1) The isolated organ responds to electrical excitation of its nerves 

 by monophasic electromotive changes, indicated by electrical currents- 

 which traverse the tissue from the head to the tail end ; this response 

 commences from 0'0035" at 30 C. to 0'009" at 5 C. after excitation, 

 the period of delay for any given temperature being tolerably constant, 



(2) The response occasionally consists of a single such monophasic 

 electromotive change (shock) developed with great suddenness, and 

 subsiding completely in from 0*002" to 0'005", according to the tem- 

 perature ; in the vast majority of cases the response is multiple, and 

 consists of a series of such changes (shocks) recurring at perfectly 

 regular intervals, from two to thirty times (peripheral organ rhythm) ; 

 the interval between the successive changes varies from 0'004" at 

 30 C. to O'Ol" at 5 C., but is perfectly uniform at any given tempera- 

 ture throughout the series. 



(3) Such a single or multiple response (in the great majority of 

 cases the latter) can also be evoked by the direct passage of an induced 

 current through the organ and its contained nerves, in either direc- 

 tion heterodromous (i.e., opposite in direction to the current of the 

 response) or homodromous. 



(4) The time relations of the response are almost identical whether 

 this is evoked by nerve-trunk (indirect) stimulation, or by the passage 

 of the heterodromous induced current. 



(5) There is no evidence that the electrical plate substance can be 

 excited by the induced current apart from its nerves, i.e., it does not 

 possess independent excitability. 



(6) The organ and its contained nerves respond far more easily to 

 the heterodromous than to the homodromous induced current, and the 

 period of delay in the case of the latter response is appreciably 

 lengthened. 



