FESSARD: ACTIVITY OF ELECTRIC PLATES 505 



C. Nevertheless, as Rosenberg points out in his Review on the sub- 

 ject,^'^ it seems unlikely that the plate has only this passive role of 

 support. According to our views, the main difficulty of a purely nervous 

 theory lies in the fact that the orientation of the discharge does not 

 agree with the symmetries offered by the nerve distribution. 



An electric organ is sometimes described as an accumulation of modi- 

 fied motor end-plates. This view is more in agreement than any other 

 with the ontogenic facts and with the analogies suggested by histology. 

 There are many nuclei in the plate near the innervated face, as in the 

 sarcoplasmic sole of the striated muscle. Couteaux recently described, 

 at the myoneural junction, a rod-like structure which is strikingly 

 analogous to that long believed to be specific of electric organs.^* 



The existence, now well established, of a localized response at the 

 nerve-muscle junction (end-plate potential, e.p.p.), preceding the 

 muscle fiber propagated impulse, renders the analogy still more evi- 

 dent. This e.p.p., like the discharge, is accompanied by an impedance 

 change that follows the same time-course as that observed in electric 

 organs (Katz^*) : i.e., a non-delayed rising phase and a maximum ef- 

 fect near the inflexion point of the potential variation. 



Our experiments on small isolated fragments contribute to show that 

 Hypothesis A cannot be retained, as it is really impossible to isolate the 

 plate as a functional effector unit. They are also more in agreement 

 with Hypothesis C than with B. 



a. AVe thought it useful, at first, to revert to the degeneration test, 

 for the observations mentioned by Garten^^ were not sufficient in num- 

 ber, and the methods for electrical detection have improved since that 

 time. 30 animals were operated on and examined at different inter- 

 vals after nerve sections on one side. Some survived more than 2 

 months, and this was sufficient to detect histological signs of alteration 

 in the terminals (Fessard and Pezard-°). Such signs began to appear 

 on our Torpedoes only 5 or 6 weeks after the operation (average tem- 

 perature 14° C). Before that, the organs were found excitable, al- 

 though needing more and more current. Excitability in any form 

 (electrical, chemical, mechanical) totally disappears after about 7 

 weeks. Osmic acid staining then shows fragmentation of the last 

 branches. Deprived of its terminal innervation, the electric organ is 

 decidedly incapable of activity. 



b. No sound conclusion can be deduced from the old results on 

 poisoning by curare. Most of the previous experimenters (namely^ 



