Udder: artificial introduction of bacteria into, 32; milk germ-free in, 19; infection of, 28; washing, 89; tuberculosis in, 87. Viscogen, 132. Water: as a source of infection, 61. Whey, pollution of vats, 23; method of preserving, 25; treatment of, in vats, 25. Whitewash, 81. Wisconsin curd test, 76. Yeasts: alcoholic ferments in milk, 73; fruity flavor in cheese, 186; gassy due to yeasts, 186; in bitter cheese, 189; in canned butter, 159; kephir, 72.