But One Drop...
I am truly awestruck at the fact that just one single drop of Our Lord's Precious Blood would have been sufficient to save us, but that His love for us compelled Him to shed every last drop! I am also acutely aware of how much I need the cleansing power of His blood. When I returned to Mass, I eventually found myself uttering the following prayer silently at the elevation of the chalice: "Into your cup I pour my joys, pains, sorrows and trials; may Your Precious Blood cleanse me, heal me in body and soul, and enable me to do Your will this and each day that You grant me." I don't know if this is a prayer that I heard somewhere along the way in my youth, or something that the Holy Spirit gave me upon my return to the Church. Whatever the case may be, I pray Our Lord finds it pleasing. I have a feeling He does or He would have caused me to stop saying it.
So much for my humble musings. Here is an excerpt from Blessed Pope John XXIII's Apostolic Letter. You can read the letter in its entirety by clicking the link.
Blood that but one drop of has the world to win
All the world forgiveness of its world of sin. 
Unlimited is the effectiveness of the God-Man's Blood -- just as unlimited as the love that impelled him to pour it out for us, first at his circumcision eight days after birth, and more profusely later on in his agony in the garden, in his scourging and crowning with thorns, in his climb to Calvary and crucifixion, and finally from out that great wide wound in his side which symbolizes the divine Blood cascading down into all the Church's sacraments. Such sur passing love suggests, nay demands, that everyone reborn in the torrents of that Blood adore it with grateful love.
The Blood of the new and eternal covenant especially deserves this worship of latria when it is elevated during the sacrifice of the Mass. But such worship achieves its normal fulfilment in sacramental communion with the same Blood, indissolubly united with Christ's eucharistic Body. In intimate association with the celebrant the faithful can then truly make his sentiments at communion their own: "I will take the chalice of salvation and call upon the name of the Lord. . . The Blood of our Lord Jesus Christ preserve my soul for everlasting life. Amen." Thus as often as they come worthily to this holy table they will receive more abundant fruits of the redemption and resurrection and eternal life won for all men by the Blood Christ shed "through the Holy Spirit." Nourished by his Body and Blood, sharing the divine strength that has sustained count less martyrs, they will stand up to the slings and arrows of each day's fortunes -- even if need be to martyrdom itself for the sake of Christian virtue and the kingdom of God. Theirs will be the experience of that burning love which made St. John Chrysostom cry out:
Let us, then, come back from that table like lions breathing out fire, thus becoming terrifying to the Devil, and remaining mindful of our Head and of the love he has shown for us. . . This Blood, when worthily received, drives away demons and puts them at a distance from us, and even summons to us angels and the Lord of angels. . . This Blood, poured out in abundance, has washed the whole world clean. . . This is the price of the world; by it Christ purchased the Church... This thought will check in us unruly passions. How long, in truth, shall we be attached to present things? How long shall we remain asleep? How long shall we not take thought for our own salvation? Let us remember what privileges God has bestowed on us, let us give thanks, let us glorify him, not only by faith, but also by our very works. 
If only Christians would reflect more frequently on the fatherly warning of the first pope: "Look anxiously, then, to the ordering of your lives while your stay on earth lasts.