August, 1%5] SHORT PAPERS 497 SHORT PAPERS The Determination of Selenium in Soils and Sediments with 3,3’-Diaminobenzidine BY R. E. STANTON AND ALISON J. McDONALD (Department of Geology, Imperial College of Science and Technology, London, S. W.7) THE use of 3,3’-diaminobenzidine for determining selenium was de