242 Papers from the Department of Marine Biology. 



Two methods of desirable experimentation presented themselves. 

 One was to in some way reverse the natural current in order that it 

 might pass in a reversed direction through the cells for some long pe- 

 riod. This was found impracticable in the time at my disposal. The 

 electric organs could not be reversed by an operation, owing to their 

 large size and vital connections; still less could the brain-parts be dis- 

 placed or operated upon. It was attempted to disconnect the electric 

 organ from the brain by an incision which might cut the electric nerves 

 and then to substitute an artificial current through the brain of 

 strength equal to the natural one for considerable periods, but the 

 fish all died, not being able to survive the operation. It is hoped in 

 the future to be able to do this with an improved technique. 



The second method was to excise portions of the electric lobes and 

 to subject them while fresh and living to electrical currents of various 

 kinds. This was done in 6 cases, Nos. 3, 4, 5, 6, 7, and 10. These 

 results will now be considered. 



The first experiments consisted in passing direct currents, of a 

 strength approximately equal to that of the fish's own current as found 

 passing through the brain, through the cells in question in a direction 

 at right angles to the natural current and also in a reverse direction. 

 It was not easy to estimate the strength of this current in the fish at 

 the point where it passed through the brain, but a rough estimate was 

 made and some small batteries were arranged so as to give an approxi- 

 mately equal current. This current was passed (torpedo No. 7) through 

 a cylindrical bit of the electric tissue which was cut out of the electric 

 lobes so as to be 4 mm. in diameter and 1 cm. long. This was placed 

 in a glass tube and platinum electrodes were used to lead in the current. 

 The tissue was cut so that its long axis was anterior-posterior or at 

 right angles to the dorso-ventral line through which the natural current 

 passes. 



This experimental current was allowed to pass through the tissue 

 for half an hour. Then the tissue was fixed and cut, but the sections 

 agreed exactly with the control, so that the current made no change in 

 the structure. Other currents of varying strength that approximated 

 the natural current were used, some of them clearly as strong or stronger 

 than the natural current. No. 6 was arranged so that the experimental 

 current was in a direction reversed to the natural current. The time 

 in this case was 1 hour, easily past the time during which the tissue 

 lived. In both these cases no positive result was attained, and it 

 seems to show that the plasmosome is not moved by these currents. 

 Whether it would be moved by such currents if they were applied to it 

 while it still lived, for weeks or months, can not be said. Currents of 

 this sort which do not kill the tissue have been applied to plant cells 

 by McClendon (25), also by Pentanalli (29), and to animal cells by 

 Conklin (9) and Lillie (23). 



