He saw some of the most beloved operas in the repertory, including Bellini’s “Norma” and Rossini’s “Il Barbiere di Siviglia,” as well as works that are more rarely heard today, like Meyerbeer’s “Robert le Diable” and Donizetti’s “La Favorite.”

“As he experienced opera, he had a distinctly erotic response to it,” said Ed Folsom, a professor at the University of Iowa and a director of the online Walt Whitman Archive. “The power of the voice to penetrate the ears of the listener in that way became a transporting experience.”

In 1855, Whitman described his feelings during a performance of Verdi’s “Ernani” in an article for Life magazine, writing: “A new world — a liquid world — rushes like a torrent through you.” Another of Whitman’s most vivid descriptions of opera comes from the sprawling poem “Song of Myself”:

I hear the train’d soprano (what work with hers is this?)

The orchestra whirls me wider than Uranus flies,

It wrenches such ardors from me I did not know I possess’d them

He had his favorite singers, such as Pasquale Brignoli, whom Whitman memorialized in the poem “The Dead Tenor.” Another tenor, Alessandro Bettini, is thought to have an unnamed cameo in “Song of Myself”:

A tenor large and fresh as the creation fills me,

The orbic flex of his mouth is pouring and filling me full.

But no singer seems to have influenced Whitman more than Alboni, the contralto. She “opened the possibility of both ‘heart’ and ‘art’ music,” Mr. Reynolds said.

Alboni appears in Whitman’s reminiscences; “Leaves of Grass”; and his memoir “Specimen Days.” In the opera-rich poem “Proud Music of the Storm,” he mentions her by name:

The teeming lady comes,

The lustrous orb, Venus contralto, the blooming mother,

Sister of loftiest gods, Alboni’s self I hear.

“Proud Music of the Storm” makes extravagant references to opera: “Norma brandishing the dagger,” “poor crazed Lucia’s eyes” and more, for a total of seven allusions. (The “Norma” Whitman saw was a passion project of Alboni’s. It was staged for two nights only, and the title role, normally sung by a soprano, was transposed lower to accommodate her range.)