“…The operative findings of Stabler (1934) and Way (1941) showed that the skin discoloration was due to blood in the subcutaneous tissue, as in an ecchymosis. In the same way, therefore, as in this latter condition, the exact colour of the sign may vary (Jackson, 1922;Neumann, 1928;Fallon and Manning, 1949). The abnormal staining of the subcutaneous tissue need not be confined to the umbilicus (Neumann, 1928;Stabler, 1934;Fallon and Manning, 1949), and may even involve previous abdominal operation scars (Gold, 1926;Schmitz, 1932;Smith and Wright, 1935).…”