The days within the Octave are of semi-double rite and the liturgical colour being white as on the feast itself.
The Office is as on the feast except that ferial psalmody is used and, of course, the antiphons for the psalms are not doubled. At Mattins today the first nocturn lessons are the Incipit of the book of the prophet Ezechiel, transferred from Sunday to today. In the second nocturn the lessons are from St. Bede and in the third nocturn St. Augustine's writings provide the homily.
The prescribed Mass today is of the 'resumed Sunday' celebrated in green vestments without Gloria and Creed. The second collect is of the Octave and the third Deus, qui corda. As the Gloria is not sung the dismissal is Benedicamus Domino. 'Private' Masses are permitted of the Octave with the introit Gaudeamus, Gloria, second collect of the resumed Sunday, third collect Deus, qui corda and the Creed.
Vespers are for the feast of St. Charles Borromeo, Archbishop of Milan, with a commemoration of the Octave and SS Vitalis and Agricola.
On Thursday, Friday and Saturday the fifth, sixth and seventh days within the Octave are celebrated.
In the 'liturgical books of 1962' fourth class ferial days replace the former days once graced by the celebration of the Octave. St. Charles is reduced to a third class feast of three lessons. On Saturday the Saturday celebration of the BVM takes place.