THEORY OF THE ELECTRICITY IN THE TORPEDO AND GYMNOTUS. 241 
to verify upon the gymnotus the fact that the strongest discharge is that obtained on 
including the entire length of the animal within the circuit. 
In comparing the discharge of the torpedo with that of the gymnotus, so far as it 
is possible to do so, it is somewhat surprising to see that the two discharges are not 
so far different as they should be to be in proportion to the length of the prisms in 
the two animals. 
But anatomy furnishes us with the key to this apparent anomaly, and shows us 
that the length of the prisms in the torpedo may be considered equal to that of the 
gymnotus, inasmuch as the number of elementary organs in the former is at least ten 
times as great as in the latter. 
As regards the constancy in the direction of the current in the discharge of the 
electric fish, it results necessarily from the unvarying direction in which nervous 
influence is propagated through the nerves of the electric organs. 
Experience has clearly shown that these nerves are charged with the sole function 
of exciting the discharge, so that the nervous action must constantly be propagated 
in a direction from the brain to the nervous extremities; the direction in which the 
separation of the two opposite states of electrical excitement ought to take place in 
the electric organ, must also necessarily be constant. 
Finally, it results from all that has been said above, and it is proved by a vast 
number of experiments, that there exists between the nervous force and the electric 
states developed in the electric organs of fishes, that same relation or degree of in- 
tensity which always exists between two phenomena of which one is the cause of the 
other, such as exists between the electric current and the magnetism which it gives 
rise to. 
In effect, without stopping to insist too much on what may be but vague in the 
physiological data, I cannot but admit that the nervous force increases independently 
of the will, with every increase in the activity of the functions of circulation and of 
respiration, and of every act of nutrition, as also under the influence of certain agents 
introduced into the organism. A great many experiments have fully convinced me 
that the electric shock of the torpedo increases with these same vital actions. Thus 
the torpedo in water, a little above the ordinary temperature, produces stronger dis- 
charges ; the effect is precisely opposite if the respiration or the circulation of the 
blood of these fishes be hindered. The torpedo and the gymnotus give discharges 
decreasing in strength in proportion to the number given, and they reacquire their 
faculty of giving more powerful shocks after an interval of repose. The torpedo, over- 
excited by nux vomica, gives shocks more powerful than usual. This last and the 
preceding facts establish the connection between the intensity of the nervous force 
and that of the electric discharge of fishes. 
I trust that I have demonstrated in this memoir, which contains the summary of 
my numerous researches upon the phenomena of electric fishes, that there exists in 
the electric organs of these fish a very simple case of relation between nervous force 
and electricity, established by well-determined laws. 
Pisa, January 184 7. 
MDCCCXLVII. 2 I 
