“…Even when the diagnosis is considered it may be difficult to prove, and it is often considered too late, or missed (Weiss, Perry, and Shevky, 1948;Wadsworth, 1951;Ley and Sanders, 1956;Sigtenhorst and Gingrich, 1957;Veirs and Davis, 1958;Anderson, Roberts, Gonzalez, and Chick, 1959).…”