I This chapter cites only a few original articles from the relevant literature. It emphasizes work on the lactic acid bacteria during the period between about 1936 and 1952 and is an extension of previous accounts of this subject (75,79). Reviews that cover nutritional requirements of both these and other microorganisms in greater detail are available (16,18,55,77,34). Reviews dealing extensively with development and use of microbiologic assays are also available (1,3,77) . A useful anthology of papers in bacterial nutrition has appeared (35).