Calamus in ecclesiastical usage, is
(1) the reed the single upright shaft which supported the table of an altar, called also Columella. In the 5th century there were, according to local usages, two or four pillars, and a fifth, in the centre, which supported the reliquary, was sometimes added, as in St. Martha's at Tarascon, St. Agricola's at Avignon, and one at Marseilles, formerly at St. Victor's Abbey. The space between these columns served as a sanctuary for fugitives.
(2) Called also Fistula, Siphon, and Canna-ai narrow tube or pipe of precious metal, which was for some time used after the 10th century, or, as some say, a still earlier date, in the Western Church, by the communicants, for suction, when partaking of the chalice. Bishop Leofric, in 1046, gave a silver pipe to Exeter Cathedral; William Rufus gave other kinds to Worcester. The custom was long retained at St. Denys and Cluny, at the coronation of the kings of France; and the pope still, at a grand pontifical mass, uses a golden pipe at communion when he celebrates in public together with his deacon and subdeacon. The Benedictines and Carthusians communicated the laity with a reed in Italy, in memory of the bitter draught of vinegar, gall, and myrrh offered in a reed to the dying Saviour, on the cross, and also to avoid any risk of spilling the consecrated wine, and to obviate the repugnance of some persons to drinking from the same cup with others.