Volume 15, Bulletins 175-184. (175) Chemistry of Butter Making: II. The Nature of the Fatty Materials in Buttermilk and the significance of Certain Buttermilk Testing Methods; (176) Physiologic Factors Affecting the Germination of Seed Corn; (177) Iowa's Population Prospect; (178) Effects of Lime on the Hydrogen-Ion Concentration and Base Exchange Complex of Gundy Silt Loam; (179) Studies on Acetylmethylcarbinol and Diacetyl in Dairy Products; (180) Disproportionate Subclass Numbers in Tables of Multiple Classification; (181) Passing an Alternating Electric Current Through Food and Fruit Juices; (182) Physiological Behavior of Grimes Golden Apples in Storage; 9183) Bacteriology of Cheese: I. Effect of Pasteurizing the Milk on the Nitrogenous Decomposition in Cheddar Cheese; (184) Cost of Production in Agriculture