« OMNIS EXPERTEM MACULAE MARIAM ». — Hymn of Vespers for the feast of the apparition of Our Lady of Lourdes, composed by Leone XIII.
The author briefly describes therein the history of the Shrine and concludes with an invocation to the Virgin.
BIBL.: G. Bossi, Gli inni del Breviario romano, Rome 1919, p. 123; V. Terreno, Gli inni dell'Ufficio divino, Mondovì 1932, pp. 178–79; A. Mirra, Gli inni del Breviario romano, Naples 1947, pp. 168–69. Silverio Mattei