GALVANISM.
The galvanic battery is the source of a chemical, continuous current, and the properties of this current are very different from that furnished by the faradic battery. The current results from the immersion of two dissimilar metals in some solution which will decompose them. One of the metal plates is more readily affected than the other, and when the plates are connected together the current starts from the affected plate towards the one least affected. This hitter plate receives the electricity and gives it off, whence its external extremity is known as the positive pole, the external extremity of the other plate to which the current returns being called the negative pole. The effect of the current received from one or the other of these poles is markedly different, and on the thorough appreciation of these differences will depend the therapeutic results obtained from the use of the galvanic current. The characteristics of these poles may be expressed as follows: The negative pole is more active than the positive, the chemical effect being greater; it is the painful, irritating, caustic pole, and its tendency is to destroy, to produce hemor rhage. The positive pole is anesthetic, the least painful, causes absorp tion and tends to check hemorrhage. Apostoli has shown that the cicatrix formed by the positive pole is essentially different from that formed by the negative. From the former we have " a hard, retractile, " from the latter "a soft, non-retractile" cicatrix, and these differences in caustic action may, as we will see, be used to great advantages in certain morbid conditions of the female genitals.
It is not per se a very essential matter as to what special form or in;.kt., of galvanic battery the gynecologist possesses. This is a matter which will depend on the taste and the means of the individual. It is, how ever, of prime importance to own a battery containing an ample number of elements for routine purposes, and it is wise to select a cell which will require the least possible attention. The batteries which we figure are those with which we are personally familiar, and the implication is not that they are superior to those of other manufacturers. It is desirable to have at least thirty-six to forty cells at one's command, especially when the generating fluid is of the kind which requires frequent renewal, and where the cell is not sealed, and therefore where there is constant loss by evaporation. Individual taste may be consulted as to whether the battery shall be portable or stationary, although whore electricity is used in routine daily practice it is, for obvious reasons, advisable to possess both forms. In the stationary battery the elements may be either enclosed in a ease or cabinet, or else, where in particular the Leclanch6 cells are used, they may be placed in the cellar or closet and thence connected with a key-board on the office wall. Many of the stationary batteries furnish
both the galvanic and faradic currents, and are so arranged that the gal vanic may be readily interrupted, thus placing at our disposal the galvano-faradic current. Obviously it is advantageous to possess a com bination battery provided only that the faradic elements are independent of the galvanic. Every battery is furnished with a current selector which enables us to bring as many of the elements as is desired into the circuit.
Whatever the form of battery it should be carefully attended to in order that the connections be kept clean and the instrument not damaged dust or moisture, otherwise the instrument will fail in what is required of it and there will be inevitable disappointment in the obtained results. Beyond these general remarks we do not deem it necessary to speak about the elementary principles which underlie the use of the battery.. The manner of making connections, of immersing the elements,.of filling the cells, etc., are points which can best be learned practically and must he so learned before the force generated can be used intelligently. The gynecologist must know his battery and how to use it and not misuse it, even as the engineer must know his engine in order to obtain the requi site speed without injury to the source. A very essential point, on which we would lay renewed stress, is the strict necessity of recognizing and of differentiating the positive from the negative pole. The majority of gal vanic batteries in use to-day are provided with a so-called pole-changer which will tell us at a glance which is the negative and which the positive pole, and which also enables us to change these poles at will, something which in gynecology is rarely advisable during the application of elec tricity. At the outset we should determine which pole we wish to utilize as the active one to meet the special indications, and it should remain the active one unless the indications change. When the properties of .the galvanic current are thoroughly understood, the operator, bearing in mind the peculiar properties of the two poles, will have no difficulty in selecting the active one for the special case. Thus, in general, when lie wishes to lessen congestion, to check hemorrhages or leucorrheal dis charges, to allay pain, he will choose the positive pole as the active one: on the other hand, when he aims at cauterization, at stimulation, at caus ing absorption, lie will select the negative as the active pole. The effect of these poles, in degree, will vary, of course, with the intensity of the current, a point to which we will refer somewhat at length further on. By the term active pole we mean the one which is directly applied to the organ or part which Ave aim at affecting, and this we will amply illustrate in the discussion of the special uses of electricity.