In the summer here they use “tough milk” which they make in the following way. When they are making cheese and the cheese has been removed, they pour the whey into a container and let it stand and ferment for a while. When they next make cheese, they pour the new lukewarm whey onto the whey that has already fermented, and so it goes on. It must not be poured on when hot, only when lukewarm. The longer this stands the better, and eventually it becomes so tough that it can be stretched like a string from one wall to the other. Indeed, if a container is filled to the top and put in a cellar with as little as a single drop overflowing, the whole container will empty itself, so great is the the cohesion of the particles. This is then stored for winter.