here is a tip:I'm sure Toscanini and Dmitri Mitroupulos,both two had a kind
of fotographic memory,they can see mentaly every page,every note ,and so
on.From Mitroupulos i kwnew from reading,and for Toscanini,for reading
too+testymony of a person who was at that time in charge of organization
and rehearsals,in concerts who also knew Alfredo Casella,who also in his
book "Il Pianoforte" speak about this.

Regards.
Gerardo Constantini.