SUPPURATIVE arthritis remains a relatively frequent form of joint disease despite the introduction of antibacterial agents. Chartier et al1of the Mayo Clinic covered the period from 1939 to 1957 and reported 77 cases of suppurative arthritis. Ward et al2from the Massachusetts General Hospital concentrated on the ten-year period from 1954 to 1964, reporting a total of 24 cases. Our interest in suppurative arthritis began in January 1960, and from then until 1964 we have observed 42 cases of infectious arthritis at the three universityaffiliated hospitals in the Buffalo area. Case Material Cases of infectious arthritis due to gonococcus, meningococcus, fungi, or tuberculosis were excluded on the basis that these represented specific diseases. Also, cases of pyogenic joint infection from osteomyelitis, penetrating wounds, or by extension were excluded. These were considered different problems from ordinary septic arthritis because of the nature of the cause. As a result