THE APPARATUS.

To a proper comprehension of the succeeding chapters, it is necessary first of all to be familiar with the apparatus employed in carrying out electro-balneological treatment, and I therefore proceed to give a description of this.[1] It may conveniently be divided as follows, viz.

• a. The tub;
• b. The electrodes and connections;
• c. The water;
• d. Chemicals;
• e. The batteries.

(a) The Tub. This must be made of a non-conducting material. Of substances that will answer, I will mention: wood, porcelain, soapstone, vulcanized rubber, or glass. In choosing one of these materials, regard should be had to the facility of attaching the electrodes. In this respect wood deserves the preference over all the others mentioned. Where economy is to be studied, it has a further item in its favor.

The tubs, which I have now in use for nearly three years are made of wood, and I find them to answer very well. It must not be forgotten, however, that a wooden tub requires to be well painted on the inside, in order to prevent its becoming water-soaked, because in that event it would become a conductor of electricity, and interfere to some extent, with the administration of the electric current in the bath.

The shape and size of the tub may be the same as those of an ordinary bath tub. To suit individual cases however, its length may be made to vary. The only peculiarity in its construction is at the head. Here, instead of slanting, it is made square, and the slightly concave (from side to side) board against which the back of the bather is to rest, is fitted in afterwards. This is necessary, because it is very difficult to make a wooden tub with a slanting back water-tight. If the length of the tub from outside to outside is made to measure about five feet ten inches, the back-rest fitted in at a proper slant will bring the inside of the tub to about the right length for an average male adult. All around the upper edge of the tub runs a wooden coping, which must not be fastened down however until all the attachments for conducting the current are in situ. Along that portion of the top of the tub where required—and this will depend on the situation of the binding posts presently to be mentioned—and underneath the coping, runs a groove for the reception of the wires that are to connect the carbon electrodes on the inside of the tub with the binding posts on the outside. This groove is continued vertically along the inside of the back-rest and foot of the tub respectively, to communicate at either end with the bed for the reception of the carbon plates. These vertical grooves should at their lower end be a little over ¼ inch deep, in order to admit of the wires being introduced beneath the carbons.

The face of the foot of the tub and that of the back-rest, should have in their centres (from side to side) and commencing at about five inches from the bottom of the tub, a bed for the reception of the carbons. The dimensions of these receptacles must of course correspond to those of the carbon plates to be employed as electrodes. Those which I use measure 12×8 at the head, 8×6 at the foot of the tub. They are ¼ thick. They are placed so as to have their long diameter correspond to the height of the tub. The bed which is to receive the carbon at the head of the tub must be deeper than ¼ on account of the concavity of the back-rest.

In order to adapt a tub to individuals of different lengths, it will be found advantageous to have two small vertical cleats on each side of the tub, near the foot and bottom, for the reception of a foot-board, which will practically shorten the tub and adapt it to persons of different lengths. This board may conveniently be six inches wide, and should have a number of perforations about an inch in diameter, for the transmission of the current to the feet. 1¼ pine plank is the most suitable wood to use in the construction of the tub. This is preferable to any of the hard woods, because of the greater facility of fitting in the electrodes etc. It is also the most economical.

(b) The electrodes and connections. These consist of two carbon plates, two brass binding posts, and insulated wires to connect the carbons with the binding posts, and these with the battery. The carbons are such as are ordinarily employed in the construction of galvanic batteries, and can, as well as the wire and binding posts, be procured from any house that deals in telegraph material. Their size is to some extent optional; the dimensions I have given above however answer very well.

The inside of the tub having received one or preferably two coats of paint, the carbons are now fitted in the receptacles provided for them. The next step is the attaching of the binding posts. These should be of the kind known as “single” binding posts with “wood screws.” The most convenient location for them will be found on the coping covering the horizontal portion at the head of the tub. Here the coping, as it has to cover not only the upper edge of the head of the tub, but that of the back-rest also, is of necessity much wider than at any other portion, and thus affords most room for the binding posts.

Having marked out then a site for the binding posts, say in the centre of the coping at the head of the tub—which should now be placed in position—and about two inches apart, the posts are laid aside to be put in place when the wires are all in situ, and the coping fastened down.

In order to facilitate the description of the placing of the wires by means of which communication is to be established between the electrodes and the binding posts, I shall term the end of the wire that is to be attached to the electrodes the distal, that which is attached to the binding posts the proximal end. A gimlet hole sufficiently large to admit of the passage of one wire should be made half an inch outwards from the centre of the site of each binding post. The best wire to use is about No. 16 copper wire, coated with gutta percha or rubber. The site of the posts being as above suggested, it will be found that the wire which is to connect the head electrode with one post requires to be about 18 inches long, that which runs from the other post to the foot-electrode, between eight and nine feet. The distal ends of the wires should be stripped of their coating for a length of about three inches, the proximal ends for about two inches. The denuded portion of the distal ends should be rolled up in the form of a spiral coil; this will insure their constant impinging on the carbons more certainly than could be expected from a simple straight end of wire.

The carbons having now been fitted in their beds, the distal end (coil) of the head wire is placed beneath the carbon, and the wire itself continued up along the vertical groove to either one of the gimlet holes. Through this, from within outward, the proximal end of the wire is now drawn and left for the present. The distal end of the second wire having now been placed beneath the carbon at the foot of the tub, this wire is continued up through the vertical groove, along the upper edge of the foot of the tub to the side nearest the binding post to which the wire is to be attached, along the groove on the upper edge of this side to the head of the tub, and thence to the respective gimlet hole, and through this, from within outward. The wires being now all in position, all the coping is next screwed or nailed down firmly, care being taken that the screws or nails used for this purpose do not injure any of the wires. The coping fastened down, the binding posts are now screwed down in the sites previously marked out for them. Before they are screwed entirely down, the denuded portion of the proximal end of each wire is securely wound around the screw of the respective binding post, and the posts are then 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.