[quote=Br. Rich SFO]Christ’s death was accomplished by separating His blood from His body at the crucifixion. In the Mass after the consecration but before the priests Communion he places the “Fraction” into the chalice. This is symbolic of the resurrection as well as a literal re-uniting of the Body with the Blood of Christ.
I am sorry Brother but I was unable to find this interpretation in Joseph Jungmann’s “The Mass of the Roman Rite” (1955 edition). The simpler answer to the fermentum is:
"5. The Commingling
In the present-day Roman liturgy the fraction is followed at once by the commingling: the separated particle is dropped into the chalice with the accompanying prayer that had been used in a similar way already in the papal Mass of the eighth century. Thus in the present-day ceremony on the commingling there is a survival of that ceremony in which the celebrating pope, just before his Communion, broke off a particle from his own Host and dropped it into the chalice.
But the Roman liturgy of that time also had a further twofold commingling of the species, which did not, however, form a part of every Mass. The first of these is surrounded be the deepest obscurity. It is mentioned only in the later version of the first Roman ordo, which contains the following direction even before the start of the fraction: cum dixerit: Pax Domini sit simper vobiscum, mittat in calicem de sancta. This sancta is commonly taken to mean a eucharistic particle from a previous Mass, the same that we noticed in the beginning of Mass at the entrance of the pope. In this way the continuous unity of the Eucharistic sacrifice was expressed- the same Mass yesterday and today. But the absence of a rite of this sort in the pertinent parallel documents compel us to suppose rather that the usage was merely a transient or tentative copy of another commingling which took place at the Pax Domini, probably with a particle from the oblation itself.
This second commingling was not proper to the papal or Episcopal Mass but to the Mass of priests in the outlying churches. By an acolyte, the bishop sent the priest of the vicinity a particle of the Eucharist as an expression of ecclesiastical unity, as a token that they belonged to his communion. This particle was called the fermentum. The priests dropped in into the chalice at this part of the Mass. The practice is indeed ancient. It answered to awareness, so keen in the ancient Church, that the Eucharist was the sacramentum unitatis, that this Sacrament held the Church together, and that all the people of God subject to a bishop should, if it were possible, be gathered around that bishop’s altar and receive the Sacrament from his table of sacrifice…"
If anyone is interested in moving beyond the superficial discussions of the liturgy that seem to plague Catholic message-boards (especially when Traditionalists are present) I would suggest two books: Jungmann’s “The Mass of the Roman Rite: Its Origins and Development” (make sure you get the 2 volume edition which was the first but the later editions had vast sections removed in order to fit it into one volume) and Theodor Klauser’s “Short History of the Western Liturgy”. Klauser’s book is short…200 pages including the appendices and cheap ($15) but Jungmann’s book cost me over $100 at a used bookstore.
Both were written pre-VII and the renewal of the liturgy so Traditionalists cannot complain…however, (especially Klauser’s book) anticipate the VII renewal of the liturgy and the return to a more ancient form of the Mass.