This section is from the book "A Treatise On Therapeutics, And Pharmacology Or Materia Medica Vol1", by George B. Wood. Also available from Amazon: Part 1 and Part 2.
If the muscles retain only a small portion of their electric contractility, it may be considered certain that the disease will recover easily and rapidly; and even with a complete loss of that property, a favourable result may be expected, though it will be longer postponed. When, with the loss of the contractility, there is at the same time a great diminution of sensibility, with atrophy conjoined, the cure '11 more difficult and protracted. But the remedy will almost always succeed in the end. From thirty to one hundred sittings may be re-quired, at the rate of three weekly; but, by operating at shorter intervals, the length of time required may be diminished. An intense current with rapid intermissions should be used. It is desirable to excite painful sensations; and, as these are attended sometimes with considerable constitutional disturbance, it is impossible, in many instances, to have quickly repeated sittings. Hence the length of time often required for the cure.