"This day shall be unto you for a memorial and ye shall keep it a Feast to the Lord throughout your generations; ye shall keep it a Feast by an ordinance for ever" (Exodus 12:14)
As I sang this Magnificat Antiphon at Second Vespers of the Most Precious Blood, I felt certain irony. It was in the wake of the Second Vatican Council, convened by Blessed John XXIII, an ardent promoter of devotion to the Precious Blood, that the feast of the Precious Blood was removed from the reformed calendar. This was not something that Blessed John XXIII could have foreseen.
The argument that the cultus of the Precious Blood is included in the Mass and Divine Office of the Solemnity of the Most Holy Body and Blood of Christ fails to convince me that it was necessary to suppress the feast of July 1st. Its magnificent antiphons and responsories, drawn principally from the Letter to the Hebrews and the Apocalypse, are possessed of a spiritual unction that penetrates the heart.
The Missionaries of the Most Precious Blood, sons of Saint Gaspar del Bufalo, and the religious Congregations associated with them, might think about launching a movement for the restoration of the Feast of the Most Precious Blood to the General Calendar. My esteemed confrère, Father Jeff Keyes, C.PP.S. may be able to get things moving.
In any event, the month of July is suitable for meditating the Apostolic Letter of Blessed John XXIII, Inde A Primis, on promoting devotion to the Precious Blood. Here is the text:
To his Venerable Brother Patriarchs, Primates, Archbishops, Bishops and other Local Ordinaries in Peace and Communion with the Apostolic See: Venerable brethren: greetings and apostolic blessings.
Devotion to the Most Precious Blood
From the very outset of our pontificate, in speaking of daily devotions we have repeatedly urged the faithful (often in eager tones that frankly hinted our future design) to cherish warmly that wondrous manifestation of divine mercy toward individuals and Holy Church and the whole world redeemed and saved by Jesus Christ: we mean devotion to his Most Precious Blood.
Catholic Childhood and Family Life
From infancy this devotion was instilled in us within our own household. Fondly we still recall how our parents used to recite the Litany of the Most Precious Blood every day during July.
The Surveillance and Development of Piety
The Apostle's wholesome advice comes to mind: "Keep watch, then, over yourselves, and over God's Church, in which the Holy Spirit has made you bishops; you are to be the shepherds of that flock which he won for himself at the price of his own blood." Now among the cares of our pastoral office, venerable brethren, we are convinced that, second only to vigilance over sound doctrine, preference belongs to the proper surveillance and development of piety, in both its liturgical and private expressions. With that in mind, we judge it most timely to call our beloved children's attention to the unbreakable bond which must exist between the devotions to the Most Holy Name and Most Sacred Heart of Jesus — already so widespread among Christians— and devotion to the incarnate Word's Most Precious Blood, "shed for many, to the remission of sins."
Thinking With the Church
It is supremely important that the Church's liturgy fully conform to Catholic belief ("the law for prayer is the law for faith"), and that only those devotional forms be sanctioned which well up from the unsullied springs of true faith. But the same logic calls for complete accord among different devotions. Those deemed more basic and more conducive to holiness must not be at odds with or cut off from one another. And the more individualistic and secondary ones must give way in popularity and practice to those devotions which more effectively actuate the fullness of salvation wrought by the "one mediator between God and men, Jesus Christ, who is a man, like them, and gave himself as a ransom for them all."  Through living in an atmosphere thus charged with true faith and solid piety the faithful can be confident that they are "thinking with the Church" and holding fast in the loving fellowship of prayer to Christ Jesus, the High Priest of that sublime religion which he founded and which owes to him its name, its strength, its dignity.