Chapter 18 — Part II: The Sacraments — The Holy Eucharist
Section 155. Christ the Lord, it is true, as has been explained by the Council of Trent, instituted and delivered to His Apostles at His Last Supper this most sublime Sacrament under the species of bread and wine; but it does not follow that by doing so our Lord and Saviour established a law ordering its administration to all the faithful under both species. For speaking of this Sacrament, He Himself frequently mentions it under one kind only, as, for instance, when He says: If any man eat of this bread, he shall live for ever, and: The bread that I will give is my flesh for the life of the world, and: He that eateth this bread shall live for ever.