INTRACELLULAR DEP'OSITION OF SULFUR BY SPHAEROTILUS NATANS

During the course of studies of the bacterial and algal flora of creek waters we were puzzled by the absence of any representatives of the genus Thiothrix from samples in which there was a regu-lar and abundant growth of Beggiatoa species. Associated with Beggiatoa in many of these samples was the colorless sheathed organism Sphaerotilus natans. In view of the very gross simi-larity of Sphaerotilus morphologically to the re-corded descriptions of Thiothrix, it was decided to test the ability of the organism to oxidize hydro-gen sulfide in a manner similar to that recorded for the species of the genera Beggiatoa, Thiothrix and other filamentous sulfur bacteria. MATERIALS AND METHOD