EXPERIMENT XV.
The sciatic nerve being divided about the middle of the thigh, on applying the conductors from the biceps flexor cruris
to the gastrocnemius, there ensued a powerful contraction of both. I must here observe that the muscles continued excitable for seven hours and a half after the execution. The troughs were frequently renewed, yet towards the close they were very much exhausted. No doubt, with a stronger apparatus we might have observed muscular action much longer; for, after the experiments had been continued for three or four hours, the power of a single trough was not sufficient to excite the action of the muscles: the assistance of a more powerful apparatus was required. This shows that such a long series of experiments could not have been performed by the simple application of metallic coatings. I am of opinion that, in general, these coatings, invented in the first instance by Galvani, are passive. They serve merely to conduct the fluid pre-existent in the animal system; whereas, with the Galvanic batteries of Volta, the muscles are excited to action by the influence of the apparatus itself.
From the above experiments there is reason to conclude:
I.
That Galvanism exerts a considerable power over the nervous and muscular systems, and operates universally on the whole of the animal œconomy.
II.
That the power of Galvanism, as a stimulant, is stronger than any mechanical action whatever.
III.