FESSARD: ACTIVITY OF ELECTRIC PLATES 507 



2. In the lengthwise stimulation of Torpedo columns, the latency 

 can never be reduced to less than a certain minimum (3 to 5 msec), 

 however strong the current (even if we approach the lethal value). 

 This can be explained by the special distribution of nerves in Torpedo 

 columns, if one admits that excitation is always localized at the bend- 

 ing points of the nerve branches. The situation is comparable to that 

 in which Rushton^* made his observations on excitation of bent nerves. 

 Before entering the plates, the nerve branches run along the edges of 

 the prismatic column, then each axon bends at right angles and, by mul- 

 tiple division at the bending point, sends small transverse twigs to sev- 

 eral plates. This point {"bouquet de Wagner") is at the same time a 

 Ranvier-node, and we assume, as most likely, that it is the most distal 

 one from which excitation can start in longitudinal stimulation. 



3. This assumption is confirmed by the fact that the latency is not 

 irreducible. Strong transverse stimulations lower it to less than 1 

 msec. (Auger and Fessard^), clearly showing that the long latencies 

 are due to nerve conduction in the plate plane, and not to some elabo- 

 ration process in the plate itself. When the intensity is lowered, the 

 transverse latency increases regularly, but never exceeds, in normal 

 conditions, the shortest latency observed in longitudinal stimulation. 

 This is perfectly comprehensible, if we localize the excitation at bend- 

 ing points nearer and nearer the "bouquets de Wagner," provided that 

 we adopt the current opinion, according to which the threshold values 

 diminish, the further we are from the nerve extremities. 



e. The non-existence of a relay action similar to that of the neuro- 

 muscular command is further indicated by the absence of repetitive re- 

 sponse when acetylcholine is injected intra-arterially into an isolated 

 organ,^®' ^^ although we have shown that this drug exerts, in this case, 

 a marked depolarizing effect. 



/. Other drugs were introduced into the interior of the plates by the 

 same technique as described in (6) (curare poisoning): eserine(10"*), 

 which lengthens up to more than 4 times the declining phase of the ele- 

 mentary discharge; atropin (lO"'^), which suppresses all excitability in 

 1-2 hours; curare, which has the same effect as atropin, but in doses 

 ten times larger. During the course of both intoxications, the threshold 

 intensity progressively rises. The duration of the elementary dis- 

 charge does not change or even become shorter. These data confirm 

 the cholinergic nature of the nerves supplying the organ. They also 

 add supplementary evidence in favor of the similitude between the 

 electric discharge and the end-plate potential (cf. Kuffler^*'' "). 



