MacLeod, Patricia (University of Connecticut, Storrs) and Joseph P. Brown. Fatty acid composition of lipids from Streptococcus cremoris and Streptococcus lactis var. maltigenes. J. Bacteriol. 85:1056-1060. 1963.-A method for the extraction of lipids from bacterial cells, involving grinding in a ball mill, is described. Cells of Streptococcus lactis var. maltigenes and S. cremoris yielded 5.3 and 5.5%, respectively, of their dry cellular weights as lipid. The lipids of both organisms were separated into three fractions by thin-layer chromatography. Two of these fractions have been classified: one fraction containing phospho- and perhaps glycolipids and the other containing triglycerides. The unidentified fraction was probably either mono- or diglyceride in nature. The fatty acid composition of the total lipid as well as that of each of the separated lipid components from the two lactic strains were compared.