At more than 150 services a year, the choirs of St. James Cathedral support the choir of the assembly, provide musical commentary on the texts of the Mass, and reveal something of the eternal liturgy in heaven. The fullest image at St. James of this celestial choral adoration is experienced on the Feast of Corpus Christi, when all of the Cathedral choirs join the assembly’s choir, “rank on rank,” in the unending hymn: Sanctus, Sanctus, Sanctus...