The organism Micrococcus tetragenus was first described by Koch 1 and Gaffky 2 in 1881. It is commonly found in long standing pyogenic processes in association with a variety of other organisms and in this connection is thought to be a secondary invader and a saprophyte. It has also been reported frequently as a primary cause of infection in various parts of the body, such as meningitis, otitis media, postpartum infections, acute endocarditis, septicemia and arthritis. A search of the literature, however, failed to find this organism attributed to the cause of pneumonia except in 3 instances, all of which were reported in foreign literature. The following is a brief summary of these cases: Delearde 3 in 1897 reported in detail a case of bronchopneumonia due to M. tetragenus in a man aged 49. He recovered the organism in great abundance in practically pure culture. He made note that the