Electro-physiology and electro-therapeutics : showing the best methods for the medical uses of electricity / By Alfred C. Garratt.
100/740

are moderate, as from a single pair. On the whole, lie finds that the excitability decreases according to the frequency and the duration of the current directions. He then tested these seldom alternations with different strength of currents, as from two to sixty pairs of plates in the pile. By taking a vigorous frog and subjecting the posterior legs to the action of sixty pairs for three hours together, he found that the together-drawings and twitchings of the muscles had lost scarcely any of their strength. It was only after another half hour that they began to grow some weaker; but this was increased again oil changing the current direction. After another three hours, there was no perceivable decrease in the muscle contractions from the first, although the current had now been running in all, and con- tinuously, for six hours, and that with but one change in the current. In short, it was found that only by a very long dura- tion of the current, there was noticed any further reduction in the contractions, and that by the change of the current direc- tion these were restored again. According to these results, says Marianini, there exists in liv- ing; healthy animals, a repairing- force, which was here mani- fested by restoring the contractions produced by the protracted electric current. In fact, as soon as a live frog has become weakened from the teasings of electric experiments, if it is allowed a time to rest, it reacquires its original strength, and the contractions show the same force, (without the necessity of changing the current direction,) as was observed at first. Ac- cording to him, this repairing force continues in some degree in the recently amputated frog leg, but then only for a short time, for the longer the time that has elapsed since the section, the shorter in-working of the current is required to make visible the reduction of its excitability, which simply means, lost strength, as first discovered by Volta. M. Marianini then goes on to speak of the alternations of Volta, which, from the application of very frequently interrupted currents, he observed produced convulsions, i. e., muscular con- tractions. When, by the frequent interruptions of the current, the convulsions, at first so strongly produced, begin to decrease,