Electrology History: Timeline for Permanent Methods, 1916

1916 – The direct current process was time consuming and tedious. In 1916, Professor Paul Kree of New York, developed a multiple galvanic machine. this allowed the electrologist to insert up to 10 needles in time sequence instead of spending several minutes on each hair.

~Modern Electrology: Excess Hair Its Causes and Treatments by Fino Gior