When meat is exposed to air it is first attacked by the mixed ferments, Micrococcus flavus liquefaciens, Staphylococcus, Bacillus coli, Bacillus filiformis, Streptococcus and Diplococcus, and becomes acid; at the same time, the presence of decomposition products of albumin may be detected, proteoses, amidoacids, amines and ammonia; the latter quickly neutralise the acids, and in three to four days the meat is alkaline, and has a faint putrid smell. Bacillus perfringens and Bacillus bifermentans sporogenes now make their appearance; the latter of these organisms produces amines, amido-acids and ammonia. In this stage the simple anærobic ferments are able to begin their work, and real putrefaction sets in; as this proceeds, the mixed ferments gradually disappear, and finally the only organisms remaining are Bacillus putrificus, Bacillus putidus gracilis, and Diplococcus griseus non liquefaciens. Another organism, which appears to play an important part in the decomposition of animal bodies, is described by Klein (63); he found that in bodies, which had been buried from three to six weeks, bacteria such as B. coli and B. proteus had almost disappeared, and an anærobic bacterium, which he calls B. cadaveris sporogenes, was very active. It is a motile bacillus 2–4 µ long, with flagellæ all over its surface. Spores are formed at the rounded ends, giving it a drumstick form. It coagulates milk, the clot gradually dissolving. It grows on all the usual nutritive media, but only under strictly anærobic conditions.