Structure and Polarity of Electric Motor Nerve-Cell in Torpedoes. 233 



Torpedo marmorata, No. 5, 35 cm. long (large), killed by cutting and the 

 brain divided tranversely through the electric lobes. The posterior portion 

 was fixed at once in Flemming's fluid, while the anterior part was subjected to 

 direct current of 110 volts. The tissue was inclosed in a 4 mm. glass tube and 

 was 1 cm. long. The current was applied for 30 seconds and the tissue became 

 "cooked" or whitened, with a discharge of gas at the kathode. 



Torpedo ocellata, No. 6, 36 cm. long (large), killed by cutting out the brain- 

 case. Electric lobes placed in glass tube 1 cm. long and 4 mm. square; area 

 of lumen and direct current of 4 volts was run through for 1 hour. Tissue not 

 "cooked." Was then fixed in Gilson's fluid. No control. Current passed 

 through cells in anterior-posterior direction. 



Torpedo ocellata, No. 7, 12 cm. long (small), worried so as to produce shocks 

 and then killed and the entire brain removed by cutting with knife. Brain 

 was then placed entire in 4 mm. tube. Anterior end cut off until length of 

 mass was 1 cm., submitted to a current of 4 volts for 40 minutes, when current 

 was 0.25 milleampere. Current was from posterior to anterior in direction. 

 Plasmosomes scattered in a general distribution which was decidedly median 

 in character. No control having been taken, it is assumed that the current 

 did not modify the position of the plasmosome in any way. ^ 



Torpedo ocellata, No. 8,11 cm. long (small). This fish was inclosed in a wire 

 cage so as to force it to lie on its back. It lived thus, apparently comfortably, 

 for 8 days, when it was removed and killed by the knife while upside down, and 

 the brain (still upside down) was fixed, embedded, etc., all in the inverted posi- 

 tion. The electric motor nerve-cells snowed no orientation whatever. The fish 

 had given many strong shocks before being killed. 



Torpedo ocellata, No. 9, 16 cm. long (small), killed with knife after being 

 worried, and electric lobes placed in centrifuge for 2 minutes at 40.60 times 

 gravity. Force was applied from anterior towards posterior direction, then 

 fixed in a mixture of one-half Bouin's fluid and one-half potassium bichromate 

 5 per cent. At this comparatively low centrifugal force the contents of the 

 nucleus were not visibly disturbed. Notwithstanding the centrifuging it was 

 still possible to count the percentage of ventrally placed plasmosomes. This 

 amounted to about 15 per cent. A stronger force applied by the centrifuge, in 

 this case, would have thrown the plasmosomes in a posterior direction inside the 

 nucleus, but it would have still been possible to determine the percentage of 

 ventral orientation, since the plasmosome does not come to rest at a dead 

 center, but inside of a considerable arc, its position in which indicates its 

 former amount of orientation in a line at right angles to the centrifugal force 

 applied. 



Torpedo marmorata, No. 10, 27 cm. long (medium), killed with knife; few 

 shocks. Fresh tissue was examined and showed most of the plasmosomes in 

 a median or nearly median position in the nucleus. A small portion of the 

 posterior part of the electric lobe was cut off and fixed as a control. The 

 remainder was placed in the glass tube of 4 mm. diameter and with the tissue 

 extending over 1 cm. in the tube. This was then placed on a circuit of 110 

 volts with a lamp of 10 watts inserted as a loop which embraced a lamp of 16 

 watts and the amperage registered 7 milleamperes. It was subjected to this 

 current for half an hour and the tissue fixed in Bouin. The current passed in 

 an anterior-posterior direction. 



Torpedo ocellata, No. 11,42 cm. long (very large), killed with knife; numerous 

 shocks. Living cells examined. Neurosomes particularly evident because of 

 their dark golden-brown color. Plasmosomes found both in fresh cells and in 

 sections to be oriented against the ventral side of nuclear membrane, at least 

 95 per cent. 



