The pathogenicity of certain strains of Brucella abortus for man has been demonstrated by the comparatively large number of cases of undulant fever reported in current medical literature. Because abortion is the chief manifestation of the disease in those species of domestic animals that are most susceptible to this infection, it has been suspected for a long time that Brucella abortus may be responsible for certain cases of abortion in women. Its habitual occurrence in the reproductive systems of both sexes of domestic animals, especially in placental tissue, must be considered as a gonotropic character of the organism, although few data are available to prove its predilection for the genital tract of man. In the human family Brucella abortus has been isolated from the blood, urine, stools, joints, tonsils, ovaries, and once each from an oviduct and from an epididymis as well as from practically all the parenchymatous tissues at