John XXIII, on 24 February 1960, issued the bull Inde a primis , approving for public use a Litany drawn up the Sacred Congregation of Rites in honour of the Precious Blood. Of the five such litanies approved for public use prior to the Second Vatican Council, the Precious Blood stands out as the only one to have not been set to chant in the Liber, or in the Graduale. As such, to our knowledge, there are no chant notation for it that can be called ‘official’.
The feast of the Precious Blood started as a Spanish devotion. Saint Gaspar del Bufalo later introduced the devotion to Italy, founding the Missionaries of the Precious Blood at the request of Pius VII in 1814. In 1849, Pius IX made a vow to extend the feast to the Universal Church if he recovered the Papal States. Sure enough, on 30 June 1849, the French army reclaimed the Papal States for the Church. On 10 August that year, Pius IX issued the bull Redempti sumus , fulfilling his vow, fixing the feast on the first Sunday after 30 June each year, the anniversary of the victory. This Sunday, of course, is the first Sunday of July.
Many source point at the 1911 reforms as the instigator of the transfer of the feast to 1 July. Pius X, in an effort to reduce extraneous feasts, issued his motu proprio entitled Supremi disciplinæ on 2 July 1911 , moving many feasts (Saint Joseph, the Nativity of Saint John, even Corpus Christi!) to Sunday. (A fortnight later, on 24 July, the Sacred Congregation of Rites issued a decree restoring Saint Joseph and the Corpus Christi to their proper days .) Later that year, to ensure that the number of Sundays when the dominical psalter ought to be recited is sufficiently considerable, Pius X issued the bull Divino afflatu on 1 November that year , but this apparently still kept the feast of the Precious Blood on the Sunday, as evidenced by the decree of the Sacred Congregation of Rites on 23 January 1912  intended for the Universal Church (Urbis et Orbis), and by another decree to Rome on 14 February 1914 .
In order to achieve the aims of Divino afflatu, Pius X eventually forbade the permanent inscription of feasts on Sundays, issuing on 23 October 1913 another motu proprio entitled Abhinc duos annos . Two years of juggling feasts naturally ruffled some feathers. To mollify any coetus fidelium adversely affected by the changes, the Pope, through the Sacred Congregation of Rites five days later , permitted the external solemnisation of feasts formerly celebrated on a Sunday. Thereafter, the first time we see the feast of the Precious Blood fixed on 1 July is in the Additiones et variationes, a decree of the Sacred Congregation of Rites concerning Abhinc duos annos, issued on 26 November 1914 .
Thus far, the feast was a duplex II classis. Pius XI, in commemoration of the 900th anniversary of our redemption in 1933, through a rescript issued by the Sacred Congregation of Rites on 24 April 1934 , raised the rank of the feast to duplex I classis, granting it honour equal to that of Corpus Christi, to which it would be later adduced in subsequent reforms.
In the meantime, let us try to imitate the very practice mentioned by John XXIII in his approval of the Litany: recite or sing the Litany everyday for the whole month of July!
Ut in omnibus laudetur Dominus.
 AAS 52 (1960) 545–550.
 Decreta authentica 2, no. 2978.
 AAS 3 (1911) 305–307.
 AAS 3 (1911) 350–351.
 AAS 3 (1911) 633–638.
 AAS 4 (1912) 57–82.
 AAS 5 (1913) 68–74.
 AAS 5 (1913) 449–451.
 AAS 5 (1913) 457–464.
 AAS 6 (1914) 10–12.
 AAS 26 (1934) 559–560.