Structure and Polarity of Electric Motor Nerve-Cell in Torpedoes. 237 
The table on page 236 gives a summary of the list of the torpedoes 
experimented upon, with their sizes (length in centimeters), the mode 
of killing, and the amount of ventral orientation of the plasmosome in 
the nucleus, found in each case by counting 200 cells and estimating 
the percentage as follows: the nucleus was roughly divided by the eye 
into an upper and a lower half in each of the 200 cells counted. The 
number of cells with the plasmosome in the upper half (always smaller) 
was subtracted from the number with the plasmosome in the lower half 
and the percentage which this difference was of the entire 200 was 
assumed as the percentage of differentiation or ventral orientation in 
the specimens under consideration. This seemed to be a fairly accurate 
method for this purpose. 
A few remarks must first be made as to the amount of ‘‘shocking”’ 
or electrical discharge performed by the fish under each method of 
killing. Cutting (vivisezione), as mentioned by Magini, was performed 
in 14 cases. This method was fairly quick, being hastened in order not 
to deliberately torture the fish to any great extent. It was considered 
by the writer that the usual stimulation, and teasing or worrying, which 
resulted in numerous strong shocks, produced as decided and charac- 
teristic physiological activity as that produced by torturing with the 
knife. However, even when killed by quick, deep slashes which cut 
the gills and the spinal cord and separated the upper brain from that 
part which bears the electric lobes, enough strong shocks were given 
to satisfy Magini’s condition of ‘“‘vivisezione,”’ and when the fish was 
sharply teased, frightened, and worried before this until the shocks 
began to weaken, it appears certain to the writer that any visible 
material effects on the nerve-cells, due to an immediately previous 
' large discharge of electricity, must become apparent. 
As Magini has said, when a torpedo is allowed to rest in a tank and 
is then taken from the water very quickly and cautiously by slipping 
a dissecting board under it and raising it out and on to a table and 
leaving it there for several hours until death has ensued, then the fish 
dies without giving practically any shocks. This was found to be true 
in nearly all cases. 
Poisoning the fish in any way was not a success, as with most poisons 
it gave electric discharges of considerable strength, but not enough to 
make one feel that the motor electric nerve-cells would show any 
effects. With chloroform the result was of particular interest because 
the fish remained quiescent under this drug, carefully administered, 
until all muscular action of the tail and fins had ceased. Then, in what 
the writer takes to be the critical period, when death finally arrives, 
the fish gave about 90 to 100 single, fairly strong shocks, each of which 
was spaced from the one preceding it and that succeeding it in a way 
that led him to believe each one to be correlated with a single heart- 
beat. No galvanometer was available to correctly portray this process, 
