From the Breviary of Prague, 1502, the continuation of the Bull “Transiturus” of Pope Urban IV, promulgating the feast of Corpus Christi, read in the Divine Office for the lessons of Matins during the octave.
Therefore the Savior gave us Himself to eat, so that man, who had fallen down unto death by his eating, by his eating might be lifted up unto life. Man fell through the food of the death-bearing tree, and was lifted up again by the food of the tree of life. On the former hung the taste of death, on the latter the sustenance of life; the eating of the one brought harm, the tasting of the other healing; one taste wounded, and another cured. See that whence the wound arose, thence also come forth the healing of it; whence death came forth, thence also life. And of the former it was said, “On whatsoever day thou shalt eat of it, thou shalt die,” but of the latter it is read, “If anyone shall eat of this bread, he shall live forever.” This is the bread that fully revives, truly nourishes, and most greatly enriches not the body, but the heart, not the flesh, but the soul, not the belly, but the mind. To man therefore, who needed spiritual nourishment, the merciful Savior Himself from the more noble and stronger food of this world provided for the refreshment of the soul by a holy dispensation. Fitting also was the generosity, and appropriate the working of His holiness, that the eternal Word of God, which is the food and refreshment of the rational creature, having become flesh, should bestow Himself upon the rational creature, the flesh and body of man, that is, as his food. For man hath eaten the bread of angels, and therefore did the Savior say, “My flesh is true food.”
The Communion of St. Teresa of Avila, by Claudio Coello, ca. 1670 
