He that communicates receives the whole Body and Blood of our Lord, even though he receive but a part of the Mysteries. For as one seal imparts the whole of its device to different substances, and yet remains entire after distribution, and as one word penetrates to the hearing of many, so there is no doubt that the Body and Blood of our Lord is received whole in all. But the breaking of the sacred bread signifies the Passion.
Reproduced in full. Translation: Oxford 1841 (Newman), public domain (Public domain).
Also cites: Eutychius Patriarch.