are liable to develop. In some cases, such cheeses rot. +93. Relation of moisture to acidity.+--From the preceding discussion, it is evident that the relation between the moisture and acidity is very close, in fact so intimate that in some cases it is difficult to distinguish one from the other when the quality of the cheese is considered. The proper relation of the moisture and the acidity determines the quality of the resulting cheese. If too much acid is developed during the manufacturing process, the product will be sour. If too much moisture is retained in the form of whey, the cheese will be sour. The less acid in the curd, the more moisture in the form of whey may be retained in the curd without causing a sour cheese. The proper relationship between the moisture and the acidity must be maintained or a sour cheese will result. The relation of the moisture to the acidity also has an influence on the curing. If the cheese has a low development of acidity and a low moisture-content, it will cure very slowly. The increasing of either the acidity or moisture usually increases the rate of cheese ripening, other factors being the same. The relation of the acidity and the moisture is so important that it cannot be neglected without injuring both the quality and quantity of cheese. This knowledge can be obtained only by experience. +94. Setting temperature.+--The temperature of renneting makes very much difference in the texture of the product. The enzyme rennin is sensitive to very slight changes in temperature. Below 70° F., its rate of action is very slow. Beginning with approximately 20 per cent of its maximum effectiveness at 70° F. (the curdling point for Neufchâtel), it has risen to 65 per cent at 84° F., to 70 per cent at 86° F., as used in Cheddar, to about 80 to 85 per cent at 90-94° F., as used in Limburger. At 105° F. it reaches its maximum effective working rate to fall from that efficiency to about 50 per cent at 120° F. Curdling at low temperature lengthens the time required for the same amount of rennet to curdle a given quantity of the same milk. The texture of curd produced at temperatures between 70° F. and 84° F. is soft, jelly-like, friable rather than rubbery. At 86° F. it begins to show toughening or rubbery characters which become very marked at 90° F. to 94° F. as used in Limburger. With the increased vigor of action as it passes its maximum rate of action at 105° F., the texture tends to become loose, floccose to granular. Aside from the Neufchâtel group, the working range of temperatures for the renneting period runs from about 84° F. to about 94° F., a range of barely 10° F., or the use of 65 per cent to 80 or possibly 85 per cent of the maximum efficiency of the rennet. Within this range of temperature, the curd has the physical characters demanded for making most varieties of cheese.