P RIMARY peritonitis is that type which is due to pathogenic bacteria that have reached the peritoneum by way of the blood stream, a single species of bacteria such as the pneumococcus or streptococcus being responsibIe. Secondary peritonitis is due to pathogenic bacteria which have reached the peritoneum through breaks in the continuity of the gastrointestina1 tract, more than one species of bacteria being responsibIe through thdir combined effects. Extension of infection from adjacent abscesses may also bring about a secondary type of peritonitis. Accidental and surgical wounds may Iikewise introduce bacteria into the peritonea1 cavity which resuIt in secondary peritonitis. From time to time articIes have appeared in medica literature which cite cases of “Gas Peritonitis” or “Anaerobic Peritonitis.” Differences of opinion exist over the abiIity of strictIy anaerobic bacteria to produce peritonitis without being in association with other bacteria. Bacteria reported to be present in the exudate of secondary peritonitis incIude coIon baciIIi, streptococci, staphylococci, WeIch baciIIi and anaerobic non-hemoIytic streptococci. A summary of the Iiterature reviewed reveaIs conAicting opinions on the existence of “Gas Peritonitis” or “Anaerobic Peritonitis ” as an entity. VeiIIon and Zuber30 are generaIIy credited with being the first to isoIate an anaerobic non-hemoIytic streptococcus under the name of Micrococcus faetidus, a strictIy anaerobic coccus growing in short chains and producing gas and a fetid odor in cuhures. This organism had been isoIated in pure cuIture from a case of suppurative barthoIinitis, and in association with other organisms from cases of appendicitis, Ludwig’s angina and perinephritic abscess. Since VeiIIon’s report there have appeared in the Iiterature numerous articIes, some reporting series of cases, others deaIing with isoIated observations on the recovery of anaerobic non-hemoIytic streptococci in pure cuIture and in association with other organisms from various Iesions, as we11 as from heaIthy body cavities and surfaces. Tissier2g was abIe to isoIate from cases of putrid enteritis anaerobic nonhemoIytic streptococci which he described as a new species under the name of LanceoIatus anaerobicus. WhiIe undoubtedIy the anaerobic streptococcus is a norma inhabitant of the human gastrointestina1 tract, it is possibIe that some may be introduced from the mouth in the process of swaIIowing saIiva. McDonaId, Henthorne and Thompson’* reported a case of perforated duodena1 uIcer which was foIlowed two and onehaIf months after surgica1 cIosure by a subdiaphragmatic abscess, empyema thoracis, and muItipIe Iiver abscesses. The anaerobic non-hemoIytic streptococcus was obtained in pure cuIture from the Iatter. PresumabIy the organisms originated from the spiIIed duodena1 contents. GiIbert and Lippman” recovered these organisms in 25 per cent of their cases of suppurative ChoIecystitis. There is an abundance of Iiterature on the bacterioIogy of acute appendicitis, and numerous investigators1,%4,12,21,32 h ave shown that the anaerobic non-hemoIytic streptococcus forms part of the bacteria1 flora of acute suppurative appendicitis, gangrenous appendi-