This appears to me the fittest place to say a few words in regard to the relative conductivity of the human body and water—the latter at the temperature ordinarily employed in baths, say from 90° to 95° Fahrenheit. Beard and Rockwell, in their work on Medical and Surgical Electricity,[2] state that “the human body is a better conductor of electricity than water at the same temperature.” Certain phenomena connected with the administration of electric baths having forced upon me some doubts in this respect, I made very careful experiments, both with and without the aid of the galvanometer (Bradley’s Tangent), to satisfy these. Without wearying the reader with details, I will state that the result of my experiments leaves no room for doubt that water at the temperatures stated—and still more so at 98½°—is superior to the human body as a conductor of electricity. I do not mean to be understood that water is a better conductor than every constituent of the human body; blood, for example, is a better conductor. But when I speak of the body in this connection, I take it as we find it practically, i.e., with the resistance of the skin, and especially the epidermis, superadded to internal resistances. I have no doubt that with a flayed individual it would be otherwise. I will add, that it will give me great pleasure to repeat these experiments, which are sufficiently simple, in the presence of any of my confreres who feel an interest in the subject.
Having thus cursorily considered the manner of using the electric current in the administration of a “routine” bath, and there being no remarks required concerning the water employed, in addition to what has been said in the previous chapter, a few words are in place on the subject of chemicals. As has been previously stated ([page 13]) these are added: a) to be absorbed, and thus act medicinally on the patient; b) to act on the skin; c) through chemical affinity to facilitate the elimination from the body of certain metallic substances, and d) to further the absorption of morbid deposits. Of the many drugs and medicines that no doubt may be made to answer these various purposes, I have had personal experience with but few, and of these I will mention the leading ones only. A requisite of all chemicals to be employed is their ready solubility in water. Of substances intended for absorption[3] I have used but three, viz: iron, iodine, and extract of malt. The first of these I have employed in anæmic and enfeebled conditions generally, but especially in chlorosis and chlorotic hysteria, with marked success. It has the advantage, when administered in this manner, not only of sparing the alimentary canal the frequently injurious task of becoming the medium of its assimilation, but, in addition to this, I believe that it can in this way be introduced into the blood much more rapidly and in larger quantities than when given by the mouth. The preparation which I have found, all things considered, the most eligible for this purpose, is the “tartrate of iron and ammonia.” This is very readily soluble, leaving no deposit, is assimilable, and not too expensive for the purpose. As, in my experience at least, it leaves nothing to wish for, I would consider it superfluous to discuss in this connection any of the other ferruginous preparations.
Iodine I have employed with a view to its absorption in rheumatism and gout. I cannot speak favorably of it in this connection. I have not in a single instance found a bath charged with iodine, either in the form of the tincture or of iodide of potassium, followed by results in any way differing from those of the simple galvanic bath employed in the same cases.
Extract of malt I have employed as a roborant, either alone or in conjunction with iron, in cases of debility and malnutrition, and found it of service.
Where the absorption of substances is aimed at, the galvanic current must be employed.
Where we add substances to an electric bath with a view of producing some special action on the skin, we may be guided by the same principles that govern ordinary balneology. Thus to obtain counter-irritant effects, we may add mustard or common salt; to render the bath alkaline, bicarbonate of potassa or soda, etc., etc.
An important object to be furthered by the addition to the galvanic bath of chemicals, is the elimination from the system of certain metallic substances. It will be found here that in practice we have to deal chiefly with two substances, viz: mercury and lead. That the elimination of these bodies by means of the galvanic bath is feasible, I shall endeavor to demonstrate further on. At present I have simply to consider the chemicals adapted for the purpose, and the manner of using them.
To facilitate the extraction from the system of mercury, nitric-acid has been recommended by those who have heretofore instituted this treatment. While I cannot positively deny that this substance may aid in the elimination of the metal, I am compelled to state, after its trial in several cases, that I have obtained equally good results from the simple galvanic bath. In the light of my own limited experience, therefore, I cannot insist on the necessity of adding any chemical to a galvanic bath which is administered for the purpose of extracting mercury from the body.
Where the elimination of lead is the object aimed at, I am, on the other hand, satisfied of the utility of adding certain chemicals to the water of the bath. Sulphuric acid has been suggested and used for this purpose. I can say nothing respecting its usefulness, as I have never tried it. Indeed, the results with iodide of potassium added to the bath have been so satisfactory, that I have had no occasion to try any other chemical, although almost any other of the preparations of iodine would probably answer equally well. The chemical affinity of iodine for lead affords a ready explanation of its usefulness in this respect. One ounce of iodide of potassium to each bath appears to me a suitable quantity.
I have had no personal experience with any other cases of chronic metallic intoxication than those with lead and mercury.