One morning, at a rehearsal at the Rotunda, Madame Catalani was so ill with a 
sick headache, that she could not rehearse her song ; and as it was extremely 
difficult for the orchestra, she begged of me to have it rehearsed by the band. 
Cooke asked me for the part from which Madame Catalani sang ; I gave it him. He 
placed it on one side of his music desk, and on the other, his first violin 
part, from which he was to play ; and to my great astonishment, Madame 
Catalani's, and that of all present, he sang every note of the song, at the 
same time playing his own part on the violin, as leader ; thus killing, as it 
were, two birds with one stone, with the greatest ease.

The song was one of Portogallo's, in manuscript, and had never been out of 
Madame Catalani's hands ; therefore, it was impossible that he could have seen 
it previously ; it was full of difficult divisions, of which he did not miss 
one. Had I not been an eye-witness of this extraordinary exhibition, I could 
not, as a musical man, have believed it.