Thanks to my student Brent McLean for the following quotation from Schmemann’s Journals:

“I reflect, while writing my Eucharist, about Communion, on the strange, mysterious alienation from it in the Church (on Mt. Athos - they didn’t regularly take Communion; in our churches, those who seek frequent Communion are held in suspicion). Mystically - it is the central question. The transformation of communion into the ‘sacred,’ the taboo, and, thus, a paradoxical naturalization (as awesome, demanding purification, etc.). Deafness to the absolute simplicity of “Take, eat . . . .” - simplicity and humility, which alone correspond to the absolute transcendence of the Eucharist.”

Among many other things here, Schmemann points to the underlying similarity of Zwingli and the medieval church - both products of a kind of “naturalization” of the Eucharist.