Abstract
Results of a comparison of 24 strains of Bact. pneumoniae (Friedlander''s bacillus) and 26 strains of encapsulated bacilli isolated from cases of genital infection in horses, are given. The human strains could not be distinguished from the equine by biochemical tests employed. Through application of serological tests the equine strains were found to form a homogeneous group identical to Julianelle''s Type B Friedlander bacillus.