By David Briggs They marched down the sloping concrete ramps of the Communion aisles by the thousands-Baptists, Presbyterians, Episcopalians, Congregationalists, Lutherans and even one Catholic priest. For more than a century, Christians had scattered throughout the grounds of the Chautauqua Institution in Chautauqua, N.Y., to receive the sacrament in the small churches and denominational houses...