The necessity of an alteration [electronic resource] : or, I. The mixture of the sacramental cup, II. The Oblation of the Elements as the Representative Sacrifice of Christ's Body, III. The Invocation of the Holy Ghost upon them, and IV. The Recommending the Dead in the Eucharistical Commemoration, Proved to be Essential Parts of the Christian Worship, from the Scriptures interpreted by the Testimony and Practice of the Primitive Church. Being a reply to a late Tract, entitled, No necessity to alter, &c. With an appendix, containing remarks upon a Treatise since publish'd, called, No sufficient reason for restoring the prayers and directions, &c.