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

producing an in-working of the current in the fibrils of the nerves, and, in the ultimate muscle fibres, for increase of excita- bility. Yet, according to Dr. Remak, we must always make a rigid distinction between the excitability of a nerve or muscle and its capability; for these two terms are not, in these con- nections, the same. I have never as yet been able to discover any diminution of susceptibility from the moderate use of this method of using a current, as to strength, say twenty Danicil's elements, or half power of induction currents; and as to time of each alternat- ing, say, for an average, every fifteen to thirty seconds ; and as to length of seance, say five or ten to fifteen minutes, — so far as it was shown by pain and prickle, by contractions, and other sensations. Not only so, but there is usually an increased re- sponse to the manoeuvres of the electrodes ; for where a motor nerve is embraced in the current that did not at first show any muscle twitch, it will, after a very few turns of the current- changer, respond by strong contractions in its depending muscles, or in their antagonists. This proves M. Marianini's observation to be correct, that " the induced opening contraction always indi- cates an increased preparation for the response to the production of the opposite current." We also find that this increase of sus- ceptibility is augmented all the more, the more suddenly that change in the current is produced. " The Tetanus of Ritter" — so often quoted,but, after all, seen only in the dead frog — I believe has never been observed in liv- ing men ; i. e., after employing the constant current for reme- dial purposes : nor is any moderate working of a current able to render either a nerve or muscle not susceptible to the entrance of the same or the opposite current. But still I believe this might be produced by an unwarrantable and abusive use of a very powerful and painful current, repeatedly applied and re- versed by a metallic current-changer, if persisted in for some time. So is a guano island desolate ; and when guano is too powerfully applied to a field or orchard, it is well known that it kills ; but in that very power, when rationally employed, con- sists its undeniable fertilizing capabilities. 27