Electricity has been employed for three distinct purposes, in reference to its chemical reagency: 1. for the cure of aneurisms, through its coagulating influence upon the blood; 2. for the solution of calculi in the bladder; and 3. for the abstraction of metallic substances from the system.

1. Cure of Aneurisms

It has been experimentally proved that a current of galvanism, sent through the blood in the vessels, has the effect of coagulating it. By some, this effect is ascribed to a chemical, by others, to a vital influence. It was supposed that, directed through the blood of an aneurismal tumour, it might have the same effect, and that it might thus be employed with some hope of success in the treatment of these tumours. The experiment has been tried, and some cases of apparent cure, with others of failure, have been reported. The needles for this purpose should be made of gold or platinum; because, if of steel, they might undergo chemical change, and thus become irritant in their course. They should be introduced so that their points may enter the blood, and there should be no contact between them. A battery of ten or fifteen pairs may be used, and the operation continued fifteen or twenty minutes, or longer. One of the risks incurred is of irritating the sides of the opening into the tumour, so as to form an eschar, which, on separating, may give exit to the blood. To avoid this, it has been proposed to coat the needles with shellac, except at the points; but this does not seem to have answered.*

* The following observations, in relation to this subject, are derived from a paper by Dr. Althaus, published in the Medical Times and Gazette (Aug. 1862, p. 219). Clots are produced only at the positive pole, where acids are liberated from the decomposition of the salts of the blood; while at the negative pole, where alkalies are set free, the blood is rendered more fluid. Consequently to succeed in the treatment of aneurisms, it is necessary that only the positive pole should be made to act directly on the blood. Another cause of failure is adelphia, who, after a careful investigation, reported in favour of the efficiency of the process employed. This consisted simply in passing the current from a magneto-galvanic machine through the tooth at the moment of extraction. A conductor from one pole was placed in the hand of the patient, and a wire from the other was attached to the forceps, by the contact of which with the tooth the circuit was completed. In numerous instances, the operation, according to the statement of the patients, was without pain; and the electric current, if care was taken to avoid the soft parts, occasioned little or no inconvenience. It was supposed that the nerve of the tooth, becoming benumbed by the electric influence, was rendered insusceptible to painful impression. The statements on the subject were received with incredulity by many scientific men, who did not think it possible that so powerful and speedy a benumbing effect should be produced by any amount of electric influence insufficient to occasion suffering to the patient; and many experiments afterwards made either proved less successful or failed entirely. The fact seems to be that, under the influence of a new sen-sation, and of new and strange manipulations, the attention of the patient was excited, and the cerebral centres so occupied as, in many instances, to be for the moment partially at least insensible to impressions usually productive of pain; on the same principle, probably, as that which operates when the pain of a violently aching tooth ceases entirely upon a mere visit to the dentist. It is certainly not impossible to produce a local benumbing effect by electric influence; but to do to the impression must be very powerful; so much so as to overwhelm nervous function by excess of excitement, and beyond anything that it would be prudent to employ for the mere purpose of saving pain in the extraction of a tooth.

The same measure has been employed for the obliteration of varicose veins, with apparent success, in several instances.

2. Solution of Calculi in the Bladder

The idea of destroying calculi in the bladder by means of the decomposing power of galvanism having been suggested, MM. Prevost and Dumas performed some experiments on a phosphatic calculus out of the body, by which they succeeded in partially dissolving and utterly breaking up the stone through this influence. They afterwards proved, by introducing a calculus into the bladder of a dog, and, by means of two insulated conductors passed through the urethra, bringing to bear upon it a powerful battery, that the operation might be performed with safety, and with some chances of success within the body. But I am not aware that any useful results have been obtained by the process; the prominent objection to it being the insoluble character of the urinary calculi, which prevents a vigorous decomposing influence from being exerted upon them.

3. Elimination of Metallic Substances from the System

In the first edition of this work, an account was given of a plan of withdrawing metallic substances from the system, by the agency of galvanism. The patient, seated on a wooden bench in an isolated metallic bathing tub, containing water slightly acidulated with nitric, muriatic, or sulphuric acid, held in his hand a conductor from the positive pole of a galvanic battery, the tub being connected with the negative pole. It was thought that, through the agency of the current, the metallic salt in the system was decomposed, and the metal, being withdrawn, attached itself in patches to the sides of the tub. Reflection has convinced me, what I was at first disposed to believe, that such a result in the human system is quite impossible; and Prof. E. H. Clarke, of Boston, states that he has satisfied himself of its impracticability by numerous experiments. (Am. Journ. of Med. Sci., N. S., xxxiii. 74).

Some years since, much attention was paid to the asserted advantages of electro-magnetism as an anaesthetic agent in the extraction of teeth. Dr. J. B. Francis, claiming to be the discoverer of the principle, secured his right under our patent laws to its exclusive application. The subject was examined by a committee of the Franklin Institute of Philthe use of faradisation instead of galvanization ; the former having little influence in promoting coagulation. The character of the needle used is also of some importance, the most oxidizable metal being preferable. Therefore, in the treatment of aneurisms, "a steel needle covered with zinc, and connected with the positive pole of a pile of twenty pairs of Bunsen's, Grove's, or Daniell's battery, feebly charged, should be inserted in the centre of the sac, and the circuit closed by placing a metallic plate, connected with the negative pole, on the surface of the tumour." Coagulation is produced in fifteen or twenty minutes. (Note to the third edition).