[The doctrine of the immaculate conception] so filled the minds and souls of our ancestors in the faith that a singular and truly marvelous style of speech came into vogue among them. They have frequently addressed the Mother of God as immaculate, as immaculate in every respect; innocent, and verily most innocent; spotless, and entirely spotless; holy and removed from every stain of sin; all pure, all stainless, the very model of purity and innocence; more beautiful than beauty, more lovely than loveliness; more holy than holiness, singularly holy and most pure in soul and body; the one who surpassed all integrity and virginity; the only one who has become the dwelling place of all the graces of the most Holy Spirit. God alone excepted, Mary is more excellent than all, and by nature fair and beautiful, and more holy than the Cherubim and Seraphim. To praise her all the tongues of heaven and earth do not suffice.
Everyone is cognizant that this style of speech has passed almost spontaneously into the books of the most holy liturgy and the Offices of the Church, in which they occur so often and abundantly. In them, the Mother of God is invoked and praised as the one spotless and most beautiful dove, as a rose ever blooming, as perfectly pure, ever immaculate, and ever blessed. She is celebrated as innocence never sullied and as the second Eve who brought forth the Emmanuel.
Cf. Immaculate Conception and America, and A Short Treatise on the Immaculate Conception.
N.B. The chant "Tota pulchra est" at the minute 17:00.