On July 30, 1944, a 4-year-old Belgian mare was admitted to the Stange Memorial Clinic with a collar gall on the top of the neck. Such a gall is popularly known as a sitfast, which is caused by collar pressure on the top of the neck interfering with vascular supply to the area, resulting in necrosis. In time a definite necrotic plug or "core" forms. This pressure is frequently caused by a poor fitting collar or from the use of heavy, swinging tongue machinery.