Structure and Polarity of Electric Motor Nerve-Cell in Torpedoes. 255 
EXPLANATION OF PLATES. 
All figures represent parts or the whole of electric motor nerve-cells from either Torpedo 
marmorata or Torpedo ocellata, which the writer believes to interbreed and to be structurally 
the same. 
Magnifications are not given, because absolute measurements of the average cell are given 
in the text. 
Where the results of experiments are shown the natural direction of gravity and the 
natural direction of the electric current are indicated by an arrow with one barb, while the 
applied centrifugal force and the applied experimental current are indicated by an arrow 
with two barbs. 
Puate 1. 
Fic. 1. A normal cell from Torpedo marmorata, No. 16. Fixed in Bouin’s fluid to which 
5 per cent potassium bichromate was added. Iron hematoxvlin. Shows large and numerous 
spindle-shaped chromophyllic bodies; also smaller, round, and deeper-stained neurosomes 
situated between chromophyllic bodies. One large and one small plasmosome. No telo- 
nucleolus. Typical chromatin bodies. 
Fic. 2. A normal cell from Torpedo ocellata, No.1. Bouin fixation. Cut in celloidin after 
bulk-staining with borax carmine and hemalum. One large and one small plasmosome. 
The small plasmosome lies inside of a telonucleolus. Several elongate and darker-staining 
nerve-sheath nuclei outside of cell; also three larger, rounder, and lighter-staining neuroglia- 
cell nuclei. 
PLATE 2. 
Fig. 3. A living cell from Torpedo marmorata, No. 16, seen with 2 mm. apochromatic 
objective, under very slight pressure of cover-glass and with iris diaphragm well cut down 
to bring out refractive properties of cell-structures. Plasmosome, karyosomes, nuclear 
membrane, and neurosomes sharply brought out. Perichromosomes slightly brought out, 
and cytoplasm granules around nuclear membrane weakly brought out. Some trace of 
chromophyllic bodies to be seen; also of neurofibrils. 
Fias. 4, 5, 6, 7, 8, and 9, nuclei from cells of several torpedoes, to show different arrange- 
ments of plasmosomes and of telonucleolus when present. 
PLATE 3. 
Figs. 10 to 18. A series of cells from Torpedo marmorata, No. 16. Macerated for 3 hours 
in one-third alcohol and teased in very weak glycerin on slide. Distribution and color of 
neurosomes well shown. Form of individual neurosomes not well shown, as only masses 
of them appear. The functional polarity of the cell well known. Dendrites tend to gather 
at one end or pole and neurite with heaviest masses of neurosomes at the other. Cells do 
not lie in natural relative positions in plate, as selected specimens were drawn from different 
slides. 
PLATE 4. 
Fic. 19. Two cells from a section of the electric lobe of Torpedo ocellata, No. 3, through 
which a current was run from left (anode) to right (kathode). These cells show the general 
pressure on the entire nucleus in the kathodal direction, which appears to result in the 
appearance of the semilunar space on the anodal side. The other changes as described in 
the text. 
Fic. 20. A single cell from the electric lobe of Torpedo ocellata, No. 5, to which a very 
strong current has been applied for 30 seconds from left (anode) to right (kathode). Fixed 
in sublimate, stained in iron hematoxylin. Shows increased results over preceding experi- 
ments. For description see text. 
PuaTe 5. 
Fig. 21. A cell from Torpedo ocellata, No. 3, that has been subjected to a centrifugal force 
of 543 times gravity for one minute. Nucleus somewhat compressed and an equatorial 
canal formed. Plasmosomes alone moved by the force. Bouin fixation. 
Fia. 22. A cell from Torpedo ocellata, No. 20, which has been subjected to a force of 601 
times gravity for about half an hour and in a ventro-dorsal direction. Both plasmosome 
