Tuberculosis is of frequent occurrence in hogs, and, apparently, the number of hogs so affected is on the increase. So true is this in some sections of the country that packers are cautious about buying hogs from those localities. The carcasses of tuberculous animals are often so thoroughly infected with the disease as to be unfit for food, and consequently are a source of loss to the packer. Where animals are slaughtered without being subjected to careful inspection, the diseased meat is very certain to be unwittingly used for food. A knowledge of the sources of infection and of the extent to which the disease is readily spread is of primary inportance to those who must undertake the responsibility of checking it.