A simple, easily constructed apparatus for electroplating radioactive iron has been described by which certain disadvantages of other forms of apparatus have been eliminated. Sixteen samples can be plated each day without difficulty.

The technic employed for preparing the radioactive iron for electroplating has been given.

The writers are indebted to Dr. P. F. Hahn and his staff who permitted one of them (M. L.) to spend several weeks in the Biochemical Laboratory at the Vanderbilt University School of Medicine and generously gave invaluable instruction and advice.