1. The velocity of cataphoretic migration of blood cells in plasma and serum is proportional to the potential drop applied.
2. The cataphoretic velocity of red cells, polymorphonuclear leucocytes, small lymphocytes, and large lymphocytes is described for serum and plasma.
3. The relation between the electrokinetic potential of white blood cells and the differences of potential probably existing in injured tissues are correlated quantitatively.
4. This correlation suggests that migration of leucocytes to a point of injury is, in part, dependent upon the electromotive forces at play in the tissues.