Dr. F. Hueppe, who has paid great attention to this subject, describes five distinct organisms which he finds to be invariable accompaniments of lactic fermentation. One of these he isolated on nutrient gelatine in the form of white, shining, flat, minute beads. This organism has the power of transforming milk sugar and other saccharoses into lactic acid, with evolution of carbonic acid gas. It is rarely found in the saliva or mucilage of the teeth. In these are two micrococci, both of which cause the production of lactic acid, but which manifest differences in their development under cultivation. There are also two pigment forming bacteria, Micrococcus prodigiosus, which produces intensely red spots, and the yellow micrococcus of osteomyelitis. These five bacteria are so different and so constant in their properties that they must, in Dr. Hueppe's opinion, be regarded as distinct species. In addition to them there is in milk an organism resembling Mycoderma aceti, which transforms milk sugar into gluconic acid.