The earliest report of the employment of a complement fixation test for the diagnosis of lymphogranuloma venereum was made by Kitchevatz and Kitchevatz-Petrovitch.1 In this and in subsequent papers,2 specific results were claimed for the use of an antigen consisting of an emulsion of a gram-positive, non-acid-fast, spore-bearing bacillus isolated from a lymphogranulomatous inguinal bubo. Schmidt-LaBaume,3 after commenting on the indefinite and inconclusive results obtained by Frei and Musger in complement fixation studies of lymphogranuloma venereum, reported for the first time on the use of antigens prepared from lymphogranulomatous pus. The early results were encouraging, but later ones were so uncertain as to cast doubt on the procedure. Löhe and Blümmers4 could not demonstrate complement-fixing antibodies with antigens prepared from lymphogranulomatous nodes or pus. Nicolau and Banciu5 failed similarly with such pus. Coutts and his co-workers6 claimed success with an antigen