Vincenzo Cirillo, the bass of the Church of the Unity, in Boston, is a teacher who represents the old, sincere, laborious Italian school.

He came to Boston in 1873, under an engagement to teach singing at the National College of Music, and after the collapse of that institution, continued in the city, engaged in instructing his numerous pupils till the year 1880-81, which he spent abroad in the inspection of the best schools of singing in the Old World, and in the study of the latest phases of teaching as practiced in Italy.

Signor Cirillo is a graduate of the Royal Conservatory of Naples, and a member of the St. Cecelia Academy of Rome, as well as the holder of eight diplomas from various societies in Italy.

His first teacher was Alessandro Busti. During his master's sickness, Cirillo taught his special pupils, and after his death, continued at the Conservatory for five years, till the increase of his private pupils compelled him to resign his position. He also studied under Alfonso Guercia and Domenico Scafati, who shares with Lamperti and Vannuccini the honor of heading the list of modern Italian teachers.

In 1879, Cirillo was appointed director of the choir of the Church of the Immaculate Conception of Boston, where he produced several of his own compositions, the chief being a brilliant and original "Stabat Mater" for six solo voices. He has published a lecture on the Neapolitan School, a method of vocalization in three divisions, and a large number of secular compositions. He is now at work on an opera founded on a Grecian story. 

—Music and Drama, November 11, 1882: 13. 

You can find Cirillo's excellent lecture on the download page. His teaching on the "compound vowel" has been addressed on these pages multiple times, which you can access using his label.