Would musical history have turned out differently if Alexander Glazunov hadn’t been smashed out of his wits when he conducted the first performance of Rachmaninov’s Symphony No. 1 in D minor? The best of Glazunov’s own neatly carpentered symphonies hover on the verge of greatness. Perhaps if he hadn’t been such a toper — swigging from bottles of spirits during lectures at the St Petersburg Conservatory, where he was director — they would do more than hover.