“…Cardiovascular factors apparently play a considerable role as a causative factor, as has previously been pointed out by many authors (Ogura and Senturia, 1949;Gregertsen and Running, 1952;Hallberg, 1952;Woolf and Jacobs, 1961;Kirchner, 1961;Hara, 1962;Mark, 1964;Timm, 1965;and others).…”