%0 Journal Article %A PAGE, L. A. %T Proposal for the recognition of two species in the genus Chlamydia Jones, Rake, and Stearns, 19451 %D 1968 %J International Journal of Systematic and Evolutionary Microbiology, %V 18 %N 1 %P 51-66 %@ 1466-5034 %R https://doi.org/10.1099/00207713-18-1-51 %I Microbiology Society, %X ABSTRACT The bacteria which cause the psittacosis-trachoma group of diseases and which are assigned to the genus Chlamydia Jones, Rake, and Stearns, 1945, can be separated conveniently and logically into two species. This separation is based on relatively stable morphological and chemical characteristics of the organisms rather than on their presumed host or tissue preferences or on the specific serology of their cell wall antigens. The type species Chlamydia trachomatis (Busacca) Rake 1957 is differentiated from the second species Chlamydia psittaci (Lillie 1930) comb. nov., by a simple key using tests that can be performed readily in the laboratory. Each species is defined, and the laboratory tests are described. %U https://www.microbiologyresearch.org/content/journal/ijsem/10.1099/00207713-18-1-51