Often released in corrupted form, this 1952 performance, without interpolation, of Verdi’s Macbeth features Maria Callas at the near start of her quarter-century professional career as Lady Macbeth, and Enzo Mascherini, generally forgotten now except to the cognoscenti who know him as one of his era’s leading Italian baritones, in the title role. The Orchestra and Chorus of the La Scala, Milan is led by Victor de Sabata, an utterly brilliant conductor who left far to few recordings behind, but more than enough to judge to his true genius.