A singer can transmit his emotions by feeling strongly himself. Sympathy is the sole transmitter of emotion, and the feelings of an audience are excited by our own, as the vibrations of one instrument are awakened by the vibrations of another.
—Manuel Garcia, The Musician, January 1897, page 20.
Frank Herbert Tubbs was an associate editor for The Musician and wrote a column called The Voice in which the quote above appears without comment or attribution.
Tubbs also wrote a very interesting article in Werner's Magazine about a lesson he had with Manuel García which you can find using his label below.