The skim-milk is poured from the milk-pans into large tubs, and allowed to stand quiet till the cheesy matter has settled to the bottom, which requires, perhaps, half a day. Then the thin liquid on top is poured off very carefully, without stirring up the rest, through a strainer, into a large brass kettle, till it is full; but the thicker substance at the bottom is left, and not put into the kettle. Under this kettle a fire is made, and the milk heated to a certain degree, regulated by the judgment of the dairymaid, sufficient to warm other cold milk, but it must not boil. The fire is made in the kitchen, or in the summer-house, or in some other room called the cheese-house. When the milk in the kettle is properly heated, it is poured into the tub of milk which has been heated and allowed to get cold. This tub is an upright vat, open at the top, of uniform diameter, bound with wooden hoops, and generally left of the natural color of the wood; scoured very bright, but sometimes painted blue and the hoops black. It is seen in Fig. 120. When the quantity of milk is large, the dairyman puts in as much rennet as he thinks necessary to curdle the milk completely; but before and during the addition of the curd the whole is thoroughly stirred, and this stirring is continued until the stick or wooden ladle used for the purpose will stand erect in the curd. Then the dairy-woman works the curd with her hands till no further effect of the rennet in curding the milk is to be seen. It is called the cheese-curd. The rennet is prepared in the following manner: The maw or fourth stomach of a newly-killed sucking calf is taken from the other stomachs, carefully cleaned and cut into strips two inches wide, and then hung up in the chimney to be smoked and dried; or, in hot weather in summer, it is hung up in the sun. Well smoked and dried strips will keep a very long time. When these are wanted for use, they are very carefully washed and purified, and then laid in the salt brine from the butter-barrels, or in lukewarm salt water to soak. The liquid is put into bottles and laid in the cellar. For curding milk as much is taken as is thought to be necessary, which cannot be determined without considerable practice and experience. If too little is taken, the cheese is not fat enough; if more than the right quantity, it gives a disgusting acid taste. It is difficult, almost impossible, to state exactly how much rennet should be used with a certain quantity of milk, because this must be determined by its quality and its strength. Something like the following quantity is, however, taken: In a sixty-quart vat are placed about fifty rennets, prepared by drying, washing, and cutting, and a clear salt brine or butter-pickle of twenty to twenty-five degrees strength is added. In smaller quantities the proportion of rennet is about one and a half quarts to a rennet, or even less. This dried maw can be bought everywhere in packages of twenty-five pieces each.