Reaction of cells to the galvanic current in tissue cultures

By applying a weak constant galvanic current (strength 2-4 billionths of an ampere, density approximately 1/1000-1/2000 δ, nonpolarizable electrodes) to tissue cultures made according to Harrison's method, the following observations were made:

The galvanic current has a directing influence upon the cell and fiber outgrowth in the cultures so that this occurs almost entirely along the lines of force in the galvanic field. Whereas in the control preparations the outgrowth occurs in all directions, cell movements under the influence of a galvanic current take place toward the anode and the cathode. The cell processes growing toward the anode show morphological differences from those growing toward the cathode. A new biological cell character may in this way be revealed.

If a weak electric current by means of a single conductor is drawn through the culture, the outgrowth of the fibers and cells always takes place perpendicular to the conductor. Bok has called attention to the fact that in the living organism the nerve fibers grow out from the spinal cord perpendicular to the long Jiber paths growing down from the brain stem. Kappers has tried to explain this as a galvanotropic phenomenon. To this observation, an interesting analogy is thus found in tissue cultures.

The hypothesis of Kappers, as the main result of this author's work on “neurobiotaxis,” that electrical forces are determining factors in the outgrowth and distribution of the different constituents of the nervous system, has been proved to be a fact in pieces of the central nervous system of the chick cultured in vitro.

As several authors (Hyde, Mathews, Pfeffer) have pointed out, electrical currents flow in developing organisms. The currents successfully employed in our experiments correspond in range in electromotive force with those found in various embryos.