504 ANNALS NEW YORK ACADEMY OF SCIENCES 



chemical properties. However, some uncertainties persist as to the 

 particular mode of production of their electrical discharges. We are 

 still ignorant of the way in which acetylcholine may act at an inter- 

 face to generate electricity. This ignorance is general, but we do not 

 even know, in electric organs, where this active interface lies; and, to 

 assign a definite physiological significance to the plate, we are faced 

 with at least three different views. Although we are far from being 

 able to give a satisfactory answer to these three debated questions, we 

 shall briefly discuss the last two in the light of the experimental evi- 

 dence we have obtained, up to the present, in our research on the 

 Torpedo. 



I. PHYSIOLOGICAL SIGNIFICANCE OF THE ELECTRIC 



PLATE 



A. According to a current view, the electric plate is considered as an 

 element of a true effector, and this implies the notion of its physiological 

 individuality. As in the case of the muscle, this special effector would 

 be normally set into activity through a "relay" mechanism, and should 

 show, by direct stimulation, an excitability of its own. This com- 

 parison with striated muscle is all the more justified, as both effectors 

 have a common embryonic origin (the Malapterurus organ excepted). 

 On the other hand, functional analogies seem to exist between the 

 electrical discharge and the muscular contraction (Marey^^) . 



B. However, the regression of all vestiges of striation in the adult 

 stage of the more powerful electric organs; the absence of myosin (re- 

 placed by mucin^) among the proteins of electrical tissues; and, above 

 all, the simultaneous disappearance of direct and indirect excitability, 

 under different conditions (nerve degeneration, fatigue, cooling) have 

 thrown serious doubts upon the value of the analogy. Some authors 

 have gone so far as to consider the possibility of a purely nervous ori- 

 gin of the discharge. Gotch^^ wrote that "the excitatory electromotive 

 change may be nothing more than the fact that when an excitatory 

 process travels down a nerve, the nerve trunk becomes negative to its 

 terminal cross-section." The maximum value of a nerve action po- 

 tential is the same as that of an electric plate, and it is suggestive to 

 note that the elementary plate discharge and the single fiber action 

 potential of the nerve commanding the organ have exactly the same 

 duration (plate 4A, upper part) . Furthermore, the chemical data are 

 far from being opposed to this conception, which tends to reduce the 

 role of the plate to that of a simple support for a richly expanding 

 nervous branching. 



