I want to turn, in the second part of this article, to the eucharist, which is prayer par excellence. And I first want to draw attention to the scholastic distinction between ex opere operato and ex opere operantis. Certainly this distinction has led to a very mechanical attitude to the sacraments; so long as one goes through the motions then God produces the results. The distinction has probably been responsible for a good number of abuses, but it is valuable as long as it is not misapplied. I mention this because I am going to deal with the eucharist as a sacrament and as the sacrament of prayer. In this context it is most important to remember what the distinction means. Because, putting it very briefly, the first part of the mass is really all done ex opere operantis and the second part of the mass is increasingly done ex opere operato; that is to say the effect of the eucharist and our participation will depend largely on the way we prepare ourselves.