In Henry Reeves's biography I found this about Liszt:
"Liszt had already played a great fantasia of his own, and Beethoven's
Twenty-seventh Sonata in the former part of the concert. After this
latter piece he gasped with emotion as I took his hand and thanked him
for the divine energy he had shed forth. At last I managed to pierce the
crowd, and I sat in the orchestra before the Duchesse de Rauzan's box,
talking to her Grace and Madame de Circourt, who was there. My chair was
on the same board as Liszt's piano when the final piece began. It was a
duet for two instruments, beginning with Mendelssohn's Chants sans
Paroles and proceeding to a work of Liszt's. We had already passed that
delicious chime of the Song Written in a Gondola, and the gay tendrils
of sound in another lighter piece, which always reminded me of an
Italian vine, when Mrs. Handley played it to us. As the closing strains
began I saw Liszt's countenance assume that agony of expression, mingled
with radiant smiles of joy, which I never saw in any other human face
except in the paintings of our Saviour by some of the early masters; his
hands rushed over the keys, the floor on which I sat shook like a wire,
and the whole audience were wrapped in sound, when the hand and frame of
the artist gave way. He fainted in the arms of the friend who was
turning over for him, and we bore him out in a strong fit of hysterics.
The effect of this scene was really dreadful. The whole room sat
breathless with fear, till Hiller came forward and announced that Liszt
was already restored to consciousness and was comparatively well again.
As I handed Madame de Circourt to her carriage we both trembled like
poplar leaves, and I tremble scarcely less as I write."