Toscanini is excessively short-sighted. To see him peering at a score, held so that it nearly touches his nose, is to begin to understand how his memory holds fast its multitude of details. Evidently to read thus laboriously is in a measure to memorize. It is sometimes painful to see him search for a rehearsal letter in a score or for some other point that has eluded him. He rehearses everything from memory, merely referring to the score for rehearsal numbers or for confirmatoin of a detail, over which he is right 99 times in 100. Occasionally he brings his own orchestral parts – not all very good, and some too bad to be used. None meticulously marked as, for instance, are Mengelberg’s.

(Bernard Shore, The Orchestra Speaks)