Daniel Waterland, in his A Review of the Doctrine of the Eucharist, notes Clement of Alexandria’s advocation of a “spiritual presence” in the Lord’s Supper. Clement writes:
And the blood of the Lord is twofold. For there is the blood of His flesh, by which we are redeemed from corruption; and the spiritual, that by which we are anointed. And to drink the blood of Jesus, is to become partaker of the Lord’s immortality; the Spirit being the energetic principle of the Word, as blood is of flesh…
And the mixture of both—of the water and of the Word—is called Eucharist, renowned and glorious grace; and they who by faith partake of it are sanctified both in body and soul. For the divine mixture, man, the Father’s will has mystically compounded by the Spirit and the Word. For, in truth, the spirit is joined to the soul, which is inspired by it; and the flesh, by reason of which the Word became flesh, to the Word.
~ Paedogogus II.2