Structure and Polarity of Electric Motor Nerve-Cell in Torpedoes. 231 
that to which the plasmosome moved. He interpreted this as a symp- 
tom of the electro-motor activity of the cell. Again, it should be noticed 
here that he figured all his cells as giving off their neuraxes in a ventral 
direction and all the plasmosomes therefore as moving toward or 
orientated toward the neuraxes. This we now know not to be a fact. 
Figure 4 represents Magini’s conception of this orientation. 
In adult examples which were allowed to die slowly out of water by 
asphyxiation, and which consequently did not give many or violent 
shocks from their electric organ, Magini found, on the other hand, that 
the plasmosome was usually central in position, and when eccentric its 
eccentricity was slight and in various directions. Neither did the 
crescent-shaped space appear on the dorsal side of the nucleus. 
He also found that in very young 
specimens (7 em.), whose electric 
organs were not yet well developed, 
the plasmosomes in the electric motor 
cells were always central. 
He deduced from these three obser- 
vations that the movement of the 
plasmosome (“‘nucleolo’’) from a cen- 
tral position in a state of rest to this 
eccentric position just after extensive 
and continuous activity was an ac- 
companiment of the normal and ex- 
tensive physiological activity of the 
cell at time of the discharge, and he 
further concludes that this movement 
of the plasmosome is the initial phe- 
nomenon which precedes and causes 
the nerve action of this cell. (Magini, 
p..d:) 
Coggi (8) took issue with these con- 
clusions, being of the opinion that ™"® Pie ee eee 
Magini’s results were artificial and as described by Magini in the 
had been due to the osmotic action adult after death by vivisection. 
of some of his fixatives in the cases when the plasmosomes were found 
oriented in the ventral position, and especially in those cases where the 
entire nucleus had moved ventrally. The writer, being interested in 
the American form, Tetronarce occidentalis, in which an undoubted 
orientation of the plasmosome always exists, carefully studied 24 
torpedoes at Naples in the winter of 1912-13 and investigated the 
following points: (1) Is there an orientation of the plasmosome? 
(2) Granted this orientation, is it due to the temporary physiological 
activities that initiate those processes in the cell which result in the 
nervous and the electric discharge? (3) Is it, instead of such a physio- 
