232 Papers from the Department of Marine Biology. 



logical phase, a permanent condition for a considerable period of the 

 animal's life (adult life or later adult life)? (4) In case the third 

 proposition is true, is this orientation of physiological value to the 

 working of the cell (induction of electro-motor impulse) or is it of no 

 significance to this activity? (5) In case it is not a condition that lends 

 itself to the physiological activity of the cell, is the orientation due to 

 the physical properties of the nuclear organs with reference to the 

 electric current that passes through these cells at the time of discharge 

 of the electric organs? (6) In the same case as just precedes, is it due 

 solely to differences in the specific gravity of the various nuclear organs 

 and particularly to the greater weight of the plasmosome? 



The question of the orientation of the entire nucleus in the cell as 

 described by Magini, i. e., its apparent movement in a ventral position 

 with the accompanying meniscoid space on its dorsal surface will be 

 considered with the question of the polarization of the nuclear organs. 



ACCOUNT OF THE EXPERIMENTS. 



Torpedo ocellata, No. 1, 15 cm. long (small), killed with knife; gave many 

 shocks before and during operation; plasmosome placed in various positions 

 in nucleus, often touching some part of nuclear membrane. About 80 per cent 

 show a tendency to be ventral in position. A few cells contain multiple 

 plasmosomes. A larger number of telonucleoli than in most examples. 

 Perhaps 10 per cent of the cells show it. 



Torpedo ocellata, No. 2, 16 cm. long (small), killed with chloroform vapor. 

 Plasmosomes single and sometimes double ; one often lighter than the other in a 

 varying degree. About 65 per cent decidedly ventral in position and resting 

 against the nuclear membrane: Few telonucleoli. Some multiple plasmosome. 



Torpedo ocellata, No. 3, 30 cm. long (large), pithed with knife, many shocks. 

 One side of the electric lobe was subjected to a direct current of 110 volts in 

 the usual glass tube with a diameter of 4 TYITTI. and a length of the tissue mass 

 of 1 cm. Direction of current was from anterior to posterior. Sublimate 

 fixation. Current was weakened by some resistance. 



The other side of the electric lobe was subjected to 543 times gravity in the 

 centrifuge for 1 minute, then fixed in Bouin's fluid. Plasmosome was thrown 

 from a normal position to the + side of the nucleus and against the nuclear 

 wall. Force exerted in an anterior-posterior direction. A considerable amount 

 of natural ventral orientation was indicated by the new position of the plasmo- 

 somes. Plasmosomes single in cells. No telonucleoli observed. 



Torpedo marmorata, No. 4, 30 cm. long (large), killed with knife; many 

 shocks before operation. Plasmosomes show very well-developed ventral 

 orientation, about 70 per cent. Many cells seen where neurite goes off from 

 either side or from dorsal side, while plasmosome is typically oriented on ventral 

 side of nucleus and touching nuclear membrane. No telonucleoli observed. 

 Plasmosomes single. A number of nerve processes traced from various posi- 

 tions of origin in different cells. 



One bit of tissue was centrifuged for 30 minutes at 828.5 times gravity. 

 Force was exerted from head toward tail or at right angles to any possible 

 axis of orientation. 



Another was subjected to 110 volts of direct electric current in usual tube 

 of 4 mm. diameter; 1 cm. of tissue for 4 minutes. Tissue was "cooked" 

 and then fixed in Bouin's fluid. 



