New varieties of cheese are formed by mixing vegetable substances with the curd. A green decoction of two parts of sage leaves, one of marigold, and a little parsley, gives its color to the _green cheese_ of Wiltshire; some even mix up the entire leaves with the curd. The celebrated Schabzieger cheese of Switzerland, is made by crushing the skim-milk cheese after it is several months old to fine powder in a mill, mixing it then with one-tenth of its weight of fine salt, and one-twentieth of the powdered leaves of the mellilot trefoil, (_trifolium melilotus cerulea_,) and afterwards with oil or butter, working the whole into a paste, which is pressed and carefully dried. Potato Cheeses, As they are called, are made in various ways. One pound of sour milk is mixed with five pounds of boiled potatoes and a little salt, and the whole is beat into a pulp, which, after standing five or six days, is worked up again, and then dried in the usual way. Others mix three parts of dried boiled potatoes with two of fresh curd, or equal weights, or more curd than potato, according to the quality required. Such cheeses are made in Thuringia, in Saxony, and in other parts of Germany. In Savoy, an excellent cheese is made by mixing one of the pulp of potatoes with three of ewe-milk curd; and in Westphalia, a potato cheese is made with skimmed milk. Preparation of Rennet. Rennet is prepared from the salted stomach or intestines of the sucking calf, the unweaned lamb, the young kid, or even the young pig. In general, however, the stomach of the calf is preferred, and there are various ways of curing and preserving it. The stomach of the newly killed animal contains a quantity of curd derived from the milk on which it has been fed. In most districts, it is usual to remove by a gentle washing the curd and slimy matters which are present in the stomach, as they are supposed to impart a strong taste to the cheese. In Cheshire, the curd is frequently salted separately for immediate use. In Ayrshire and Limburg, on the other hand, the curd is always left in the stomach and salted along with it. Some even give the calf a copious draught of milk shortly before it is killed, in order that the stomach may contain a larger quantity of the valuable curd. Salting the Stomach.