firmly screwed down, holding the proximal ends of the wires in place. Connection is now established between the binding posts and the head and foot electrodes respectively. The vertical grooves are now to be filled in with putty and painted over, care being taken to keep the carbon free from paint. The last step towards completing the apparatus is to fasten the carbons in their beds. The simplest way of doing this is by stretching over each carbon a piece of muslin, folded double, and tacking this down around the edges. Zinc or galvanized iron tacks are best. Copper tacks should be avoided on account of their superior conductivity.

In order to be able when required to localize the current in special portions of the body, it is well to be provided with what I have termed a “surface board.” This is a piece of black walnut, say 14 in. long by 5 in. wide, ¾ thick, having in the centre a bed to accommodate a carbon plate, say 5 in. long by 2 in. wide, ¼ thick. From the centre of this bed a gimlet hole pierces the board. The denuded end of an insulated wire is drawn through this gimlet hole from without inward (toward the bed) and twisted in the form of a spiral to prevent its slipping back, as well as to insure its more certain connection with the carbon. The carbon is now placed in the bed, and kept there by a piece of muslin drawn over it and tacked down. The wire should be of sufficient length to reach the battery. I shall speak further on of the use to be made of the surface board.

c) The Water. The quantity of water may be the same as that in an ordinary bath. In those cases alone where it is intended to localize the current by means of the surface board, and to concentrate it very strongly in one spot, the water in the tub should be left low enough to leave the particular spot to be treated uncovered by this; the surface board can then be applied to this spot without the loss to the current of strength, through derived currents, inevitable in its application under water.

The temperature of the water may range from 85° to 105° Fahrenheit. As a rule the comfort of the patient may be consulted in this respect. There are certain cases, however, where an especially high or low temperature is indicated, and where the extremes mentioned have to be touched.

d) Chemicals. Where these are added to the water of the bath, it is for one of three purposes: viz. 1)—To exercise a direct therapeutic influence on the patient, either internally by being absorbed, or externally by their action on the skin; 2)—Through chemical affinity to aid in eliminating certain metallic substances from the body; or 3)—To further the absorption of morbid deposits. The various indications in these respects will be treated of in their proper places.

e) The Batteries. In the choice of this, the most important part of the electro-balneological apparatus, the greatest circumspection is necessary. Inferior instruments and such as are liable to get out of order frequently, have time and again been the means of discouraging the beginner in electro-therapeutics, and causing him to abandon the study of an art, the pursuit of which would have well repaid him for all his labor. Fortunately our manufacturers here in New York turn out very good instruments, and if a physician purchases an inferior one, the fault is his own.

Two different currents are required for the baths, viz. 1)—The galvanic, which may be employed either in the constant or interrupted (by means of a rheotome) form; and 2)—the faradic or induced current. Several manufacturers of this city turn out good and serviceable faradic instruments. Those which I have been in the habit of using for some years past are manufactured by the Galvano-Faradic Manufacturing Company, and they have given me unvarying satisfaction. By means of a recently introduced attachment to their batteries, termed the “fine adjustment,” a current of exquisite “fineness” (rapidity of interruption) is obtained, thus removing the only inferiority that has heretofore distinguished American from the best imported instruments. The instrument is very easy of management, and its liability to get out of order very small.

As however the galvanic current is of vastly greater importance in a therapeutic respect, than the faradic, so also much greater care is required in the choice of a galvanic than a faradic battery. In making choice of a galvanic battery, we have to consider its relative quantity, intensity, constancy, permanency, economy of running expenses, and facility of management. We cannot be guided here by the same considerations that guide us in the choice of a battery for office use, where the séances are usually brief and the elements taxed not nearly so much as in the administration of baths. It is not within the scope of this work to enter into a description of the various galvanic batteries that are in use. Neither do I believe that, in a therapeutic sense, there is much difference between the various batteries ordinarily found described in text-books on electro-therapeutics.

Where the battery is to be stationary, a zinc-copper battery, such as the Hill battery for example, is preferable both on account of its constancy and the economy of running it. Of this there should be fully sixty cells, communicating with the bath through a current selector, by means of which the current from any desired number of cells can be obtained. The electro-susceptibility of different individuals varies to such an extent that this is absolutely necessary. Where a portable battery is desired, the Stöhrer zinc-carbon battery will be found the most useful.

I have mentioned these two batteries simply because I have them in use, and they give me satisfaction. There are many others, however, that will answer equally well. On the whole, any battery possessing quantity and intensity in a medium degree will answer.

CHAPTER II.

MODE OF ADMINISTRATION.

I shall describe under this head the modus operandi of administering a routine galvanic or faradic bath. As it will become necessary to describe special modes of administration when speaking of the electro-balneological treatment of special diseases, the describing them now would only lead to tautologies that I am desirous of avoiding.

Taking our cue from the indications to be met in each case, it becomes necessary, according to circumstances, to use either the galvanic current, the faradic, or both successively. As modifications of the application of the currents we have to consider 1) their intensity; 2) their direction, and 3) the duration of the application.

The intensity of the galvanic current corresponds directly to the number of cells from which it is derived. It were vain however to attempt to express this in figures, because the electro-motive force of different batteries varies to so great an extent, that a number of cells of some batteries