the truth of the thing signified is surely present there

The Lord's Supper
John Calvin "can be regarded as occupying a position roughly midway between" (McGrath) the doctrines developed by Martin Luther on the one hand and Huldrych Zwingli, on the other:
"Believers ought always to live by this rule: whenever they see symbols appointed by the Lord, to think and be convinced that the truth of the thing signified is surely present there. For why should the Lord put in your hand the symbol of his body, unless it was to assure you that you really participate in it? And if it is true that a visible sign is given to us to seal the gift of an invisible thing, when we have received the symbol of the body, let us rest assured that the body itself is also given to us." (Calvin); that is, "the thing that is signified is effected by its sign" (McGrath).[65]

http://en.wikipedia.org/wiki/Transubstantiation

65.^ McGrath, A. 1998. Historical Theology, An Introduction to the History of Christian Thought. Blackwell Publishers: Oxford, p.199.