“…Radioactive sulphate was separated in the form of benzidine sulphate preparatory to the measurement of its 85S content. Although detailed studies of this method of measuring 35S have already been reported (Henriques, Kistiakowsky, Margnetti & Schneider, 1946;Young, Edson & McCarter, 1949), it was necessary to modify these procedures in order to meet the requirements of the present investigation.…”