This bulletin describes some work done in the Bureau of Plant Industry with reference to spoiled corn. This is preliminary to a further study to determine the possible connection between spoiled maize and pellagra. In the study of corn the Italians lay great stress on acidity. The bulletin describes methods of examining corn, by inspection, biologically and chemically, determining its acidity, which in sound corn should not be over 30 as measured by alkaline tests, its ash, fat, phenol and other reactions and the determination of its toxicity by animal experimentation; also a study of the microorganisms which cause it to become moldy. The work is valuable as a foundation for the final determination of the rôle, if any, that spoiled maize plays in pellagra. No conclusion has been reached as yet. Many references to the literature are given.