...The Congregation for Divine Worship [in 1969] issued an Instruction, Memoriale Domini, on the manner of receiving Holy Communion.... After recalling the development of the reception of Communion on the tongue as a fruit of "a deepening understanding of the truth of the Eucharistic mystery...", the Instruction declares that "this method of distributing Holy Communion must be retained...." It also warned: "A change in a matter of such moment, based on a most ancient and venerable tradition, does not merely affect discipline. It carries certain dangers with it...the danger of a loss of reverence for the august sacrament of the...