no regular interval between the shocks, which sometimes followed so quickly as not to be counted, while other animals could scarcely be provoked to give any shock.
The electric discharge was mostly accompanied by an evident muscular action in the animal, with an apparent swelling of the superior surface of the organs, and by a retraction of the eyes.
Two of these fish being placed in different buckets of water, one, which was irritated so as to give frequently repeated shocks, soon became languid, its shocks diminishing rapidly in intensity, and it soon died; but the other, not being irritated, continued living to the third day. And this was universally observable, that those which parted with shocks most freely soonest died.
A Torpedo, in which the nerves proceeding to the electric organs had been divided, seemed to have no power of giving shocks, but appeared just as lively as another Torpedo taken at the same time, and placed in a separate bucket of water uninjured.
Of two Torpedos taken at the same time, one had the electric organs divided. They were then both irritated equally, so that the perfect animal was soon exhausted of all power, and died; but the other, which had lost the power of giving shocks, appeared as vivacious as before, and lived to the second day.
An animal, from which one electric organ had been removed, was found still capable of giving shocks, though possibly not so strong as before.
Another fish, in which only one nerve to each organ had been divided, was also able to give shocks as before.
When they were held only by the tail or by the extremity of their lateral fins, they appeared to have no power of giving shocks.
Mr. Todd infers from these experiments,
That the electric discharge is a vital action.
That it is perfectly voluntary.
That frequent action is injurious to life, and may soon exhaust it. That an animal deprived of this power is more vivacious, and lives longer than one which exerts this means of exhausting itself.
That both organs are not necessary for giving the shock.
That all the nerves of one organ are not necessary to be entire.
That a most intimate relation subsists between the nervous system and the electric organs.
Each of these methods, says the author, is to be considered as direct, although it proceeds through the medium of Cassini's approximation, which, as here used, can only be regarded as a first step
