263 A Note on the Taxonomic Status of Strains Like ‘Campo,’ Hitherto Classified as Mycoplasma hominis, Type 2

The classification of strains similar to Mycoplasma strain PG 27 of ‘Campo ’ as Mycoplasrna hominis Type 2 should be withdrawn. These strains have now been identified as M. arthritidis. Nicol & Edward (1953) in an examination of 91 strains of Mycoplasma, isolated by them from the human genital tract, showed that all except one belonged in a single species, then termed ‘Human Type 1 ’. An additional 13 genital strains were received from other laboratories. Of these, 9 from three laboratories were found to belong to ‘Human Type 1’. A tenth strain was identified as a different species, later to be called Mycoplasma fermentans. The other three strains differed sero-logically from the ‘ Type 1 ’ and were provisionally classified as ‘ Human Type 2 ’. Edward (1954) noted later that the ‘ Human Type 2 ’ strains produced abscesses in mice when inoculated subcutaneously together with agar. This was a property that ‘Human Type 1 ’ strains did not have, but was one shared by certain rat isolates. On the other hand, Ruiter & Wentholt (1952) described abscess formation when their ‘ G ’ strain (M.fermentans) was inoculated into the foot-pads of mice. Unfor