Buffalo mozzarella comes in a ball about the size of a large fist, and the tomatoes for a Capri salad are round and usually about the same size so that the diameter of a slice of tomato is more or less equal to that of a slice of mozzarella. My husband came home once from the market with some mozzarella freshly arrived that morning. In the kitchen there was a basketful of very ripe, delicious cherry tomatoes. Victor pondered the difference in dimensions and, since he could not match the tomato to the mozzarella, he decided to reverse the procedure, matching the mozzarella to the tomato. He dropped the two into a bowl, adding a fistful of torn-up basil leaves. What we discovered was that when the salad is tossed, diced-up fresh buffalo mozzarella discharges a considerable quantity of milky whey, which merges with the juices released by the tomatoes. Together with the oil and vinegar of the seasoning, these juices form a delectable pool that, in between bites of the salad, you sop up with a crusty piece of bread. It is almost better than the salad itself.