The value of electrical treatment / by Julius Althaus.

  • Althaus, Julius, 1833-1900.
Date:
1899
Catalogue details

Licence: Public Domain Mark

Credit: The value of electrical treatment / by Julius Althaus. Source: Wellcome Collection.

    30/186 (page 18)
    lighter than any other conductor. The advantage of such electrodes will be fully appreciated by those who have endeavoured to secure an accurate adaptation of the surface of the electrodes to the head and failed to attain this desideratum through the stiffness of other conducting materials. Density of the Current. A simple record of the current-strength in MA.'s does not show us the actual electric force which may pass through a tissue at a given time; and it is equally important for us to know the density of the current, that is, the quantity of electricity passing in a unit of time through a unit of trans- verse section. The density of the current is generally calculated for the active or efificient electrode, by which we intend to act on a certain organ; while the indifferent electrode only serves for establishing the circuit, and is not taken into consideration as far as this point is concerned. The density of the current is therefore equivalent to the current-strength divided by the surface of the transverse section of the conductor, and is expressed by the formula /-< D = ^. If, for instance, the current strength is 5 MA.'s, and the surface of the electrode 5 square centimetres, the density of the current is f =1 j but if the electrode, should have a surface of 10 square centimetres, and the current- strength remain the sarne as before, then the density will be 1^=^. The density therefore diminishes in proportion as the surface of the electrode increases, and vice versa. It is therefore not sufficient, when describing a medical application of the constant current, to say that so many MA.'s were used, but it is equally necessary to state the superficial area of the electrodes which were employed. Milli-ampferage and current density are thus seen to be of the first importance for all therapeutical applications of the current, just as posology is for the use of drugs. It is.