Even if nothing but bread and wine were present in the Supper, and yet I tried, simply for my own satisfaction, to express the thought that Christ's body is in the bread, I still could not say anything in a more certain, simpler, and clearer way than, "Take, eat, this is my body." For if the text read, "Take, eat, in the bread is my body," or, "With the bread is my body," or, "Under the bread is my body," it would immediately begin to rain, hail, and snow a storm of fanatics crying, "You see! do you hear that? Christ does not say, �This bread is my body," but, �In the bread, or with the bread, or under the bread is my body!" And they would cry, "Oh, how gladly would we believe if he had said, 'This is my body'; this would have been distinct and clear. But he actually says, 'In the bread, with the bread, under the bread', so it does not follow that his body is present." Thus a thousand evasions and glosses would have been devised over the words "in, with, and under," no doubt with greater plausibility and less chance of stopping it than now.
Martin Luther, vol. 37, Luther's Works, Vol. 37 : Word and Sacrament III, ed. Jaroslav Jan Pelikan, Hilton C. Oswald and Helmut T. Lehmann, Luther's Works (Philadelphia: Fortress Press, 1999, c1961), 306.
(NOTE: I found this on another site and have not verified that the citing is accurate)