Du Bois-Reymond applied this term to signify the transference of certain medicaments by the galvanic current through the skin or mucous membrane from one point to another. The movement is a kind of osmosis or diffusion, and takes place from the positive pole—the anode—to the negative pole—the cathode. The action is mechanical, and not chemical or electrolytic. The medicaments thus transferred through the tissues have been chiefly anodynes and preparations of iodine, although experimentally, in the way of proof of the fact, many different kinds of substances have been employed for this purpose. It is necessary to the process of cataphoresis that the medicine to be thus transferred be in solution, and one capable of diffusion. The skin offers the greatest opposition to the transfer. Dr. Corning, of New York, sought to overcome the resistance of the skin by perforating it by means of a Baunscheidt-needle instrument at the point of application of the anode.

The apparatus required for the process of cataphoresis consists of a galvanic battery of the strength of five milliampéres up, of a suitable electrode for containing the medicament, and the substance to be transferred in proper form for the purpose. An ordinary sponge electrode moistened with a solution has been used successfully, but greater precision than such a method admits of should be employed. The best electrode for the purpose probably is one of carbon having an outer rim of leather or other soft material to adapt itself to the skin. A nickel-plated disk may be used also. A bit of paper or linen cloth of the proper size is laid on the electrode, and the solution is dropped on. Such disks of paper or linen may be impregnated with a defined amount of the solution, dried, and when required for use can be moistened. Dr. Morton has substituted for Dr. Petersen's paper soluble gelatinous disks duly impregnated with the drug to be used in this way.

The method of cataphoresis is employed in neuralgia chiefly, and by means of cocaine, morphine, aconite, chloroform, and other anodynes. Vesication quickly follows the application of chloroform—so easily and quickly as to make this a nice method of raising a blister.

The lithium salts are used in cases of rheumatic or gouty affections of joints. Similarly, the iodides are employed in the treatment of strumous and syphilitic affections, and in deformities arising from muscular lesions.

As the skin offers the greatest obstacle to the passage of the current and also of the anodyne solution, punctures with a Baunscheidt instrument may be usefully made in advance of the application of the electrodes. By such an expedient we have the effects of a counter-irritant superadded to the action of cataphoresis, as well as facilitating the anodyne treatment. A mixture corresponding to that in Schleich's method may be utilized under these circumstances.