| Rx. | Phosphorus, | gr. j; |
| Abs. alcohol, | fluidrachm vi. | |
| Dissolve with heat. | ||
| Glycerin, | fluidounce iss; | |
| Alcohol, | fluidrachm ij; | |
| Spts. peppermint, | minim v. | |
| One teaspoonful represents gr. 1/20. | ||
Electricity, if properly used, is capable of temporarily, and even radically, relieving the neuralgic state. The forms most often employed are faradic and galvanic electricity, though frictional electricity has also been coming into use of late, mainly as a substitute for faradism. The galvanic current is by far the most efficacious of all. This probably acts mainly by directly inducing better nutritive and better functional conditions in the nerves and nerve-centres, but the fact that it is often of use in cases of undoubted neuritis seems to indicate that it may also influence the grosser structural changes in the affected parts, if such are present. It is impossible to explain its action more exactly, and the teachings of physiological experiments do not lend us much aid.
It is probably not of much consequence which pole is used in the neighborhood of the affected nerve. It should be remembered that the peripheral nerve-trunks are so deeply buried that the electrodes cannot be directly applied to them, as they are to the exposed nerve of a frog in the laboratory, and, further, that instead of being isolated they are surrounded with tissues of good conducting power, into which the current must rapidly flow off. For these reasons the nerve near which either electrode is applied is virtually exposed to the action of both poles in almost equal degree; and although it is more customary to use the positive pole in the neighborhood of parts which are considered to be in a state of irritation, yet clinical experience has not justified the conversion of this custom into a rule. Neither is the direction of the current of material consequence.
It is, however, very important in acute cases to take care that the current-strength should not be rapidly changed; and for this reason the electrode should be drawn slowly to a distance from the nerve before it is removed, or left in situ while the current is gradually diminished by a suitable rheostat. As a rule, the former method is the more practicable.
In the treatment of acute cases moderate currents and short applications, frequently repeated, are the best. On the other hand, in cases of long standing, especially cases of sciatica, strong currents are sometimes more effective, and even interruptions and reversals of the current may be in place.
The choice of a battery is not a matter of indifference. Any stationary battery of high interior resistance will answer the purpose, but most of the portable (zinc-carbon) batteries in common use are objectionable,26 for the reason that their interior resistance is so low in proportion to that of the body that it may almost be counted out as a factor in determining the strength of the current. The latter is liable to rise, therefore, quite suddenly as the resistance of the body—i.e. the vascularity of the skin—becomes modified. This objection is obviated if a large, constant resistance (water or graphite rheostat) is attached to the battery and kept always in the main circuit.
26 Archives of Medicine, April, 1884.
Faradism probably owes its efficiency to the indirect effects of stimulation of the sensitive nerves of the skin. This may be produced either by the wire brush, which causes a sharp irritation and reddening, and is to be compared with the counter-irritants, or by the milder application of a moist or dry electrode or the hand of the operator. The latter procedure may be compared to the superficial manipulation which is sometimes so grateful, especially in nervous headaches.
The value of electricity as a general tonic should be remembered in this connection.