Question: Is there supposed to be a linen cloth covering the altar rail??
Answer: Christians knew that our Lord was going to give us His flesh to eat and His blood to drink, even before the Last Supper. Just after working His miracle of feeding the crowd with just a few loaves of bread, He gave us this promise, which would be fulfilled the following year on Holy Thursday as He celebrated the Passover Sacrifice with His disciples.1 At a relatively early date Christians came to recognize that not only was our Lord present when they received Holy Communion, but that His Body and Blood remained in each fragment of the consecrated Host and in each drop of consecrated Wine for as long as their appearances were perceptible. From at least as early as the second century the Blessed Sacrament was reserved -- in a variety of ways -- for the Communion of the sick.2 It also became a matter of some concern that appropriate reverence be paid to this Most Holy Sacrament by keeping consecrated particles from being scattered about and trodden under foot, and by ensuring that none of the Precious Blood be spilt.
A fourth century passage, often attributed to St. Cyril of Jerusalem instructs communicants:
The Church incorporated this attitude into Its official liturgical practices. Altar cloths were provided to absorb any spills, and tiny fragments of the Blessed Sacrament could be recovered from the smooth starched corporal on which rested the Host and Chalice by running the thin gold paten methodically over its front surface. The priest was directed to hold his thumb and forefinger together until they could be rinsed in the ablutions which he drank after Holy Communion.
For those who did not receive at the altar, a Communion cloth (alternatively called a "domenical," a "manutergium," a "houseling cloth" or a "communion veil") was employed to catch the Host if dropped by the priest, and in some cases to keep the communicant's bare hand from touching the Host. In some places the early Church permitted men to receive directly in the hand, while requiring women to cover their hand with the Communion cloth. Both sexes drank the Precious Blood through a golden straw called a fistula, administered by the deacon.
For several centuries, beginning about the 12th, when Communion began to be distributed only under the form of bread, and directly on the tongue, the communicants received a drink of unconsecrated wine from a chalice, which they still held with the Communion cloth. At first the Communion cloth was held at the top step of the altar, but, at least for the laity, this gave way to the Communion bench of the 15th century, and the more familiar Communion rail of the 16th century, still covered with the Communion cloth. The Communion cloth remained for the clergy who communicated at the altar step, and is mentioned in several of the monastic ordos.
In modern times the Communion cloth was called for in the Roman Ritual and Missal, although the Catholic Encyclopedia gives the Communion paten as an alternative. Apparently this was considered an abuse, for roughly ten years later the Sacred Congregation for the Sacraments issued a decree requiring the cloth, and allowing the additional use of the paten. The paten was to be larger than the paten used at the altar, and unconsecrated. At first it was given to the laity to pass from communicant to communicant, but often came to be carried by the server.
As employed during the 20th century, the cloth was handled by the acolytes for the reception of Communion at the altar, and was extended to full length for use at the altar rail. It obviously was not treated with the same minute attention as the corporal was at the altar, although the priest would have carefully recovered any visible fragments if a Host were dropped on to it. In practice, a Communion cloth was sometimes semi-permanently attached to the sanctuary side of the altar rail, and flipped over it at Communion time. This practice may have led to the exclusive use of the paten, as being less likely to scatter Host fragments.
The Communion cloth is mentioned by rubricists and remained in Ritus servandus (X. 6) of the Roman Missal until the 1960 revision of Pope John XXIII. Curiously, the Rubricæ generales (XX) of the earlier Missals did not mention the cloth among the items prepared for Mass at the credence table. The 1960 Missal removed the Confiteor with its associated prayers as well as the Communion cloth from X. 6, mentioning a Communion paten on the credence in Rubricæ generales 528.
Although, like the Confiteor before Communion, the Communion cloth seems unnecessary since the 1960 revision, it is still seen in some traditional Catholic churches. We have even heard that it is the custom for communicants to place their hands under it, as they did with the houseling cloths of old.
1. Cf. John vi.