. Carnegie Institution of Washington publication. 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 as
. Carnegie Institution of Washington publication. 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 cm.), 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. 3.) Coggi (8) took issue with these con- clusions, being of the opinion that Magini's results were artificial and had been due to the osmotic action 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 occidentali
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