Spices are an iiitegral part of the flavoring in many food prodnets. Since earliest times they have been associated with foods and have been considered in the role of preservatives along with salt, sugar, and acids, despite the fact that Leeuwenhoek found millions of microorganisms in a n infusion of whole pepper as early as the seventeenth century. The significance of Leeuwenhoek's findings has been completely overlooked and during the intervening centuries practically all the work that has been done with spices has been done on the action of spices in preventing rather than causing spoilage in foods to which they were added. Much work has been done to show the antimicrobial action of the various spices separately and in combination with foods.Several years ago in a series of experiments on pickles which were set up to determine the cause of spoilage, it became evident that the mixed spices used were responsible for the spoilage which occurred since all the other factors were controlled or eliminated. During the past year the experiments were repeated, and they confirmed the earlier results.I n the experiments reported here bacteriological tests were made on whole mixed spices, whole spices, ground spices, the oil of spices, and emulsions of the oils. Experiments were made also to study the influence of contaminated spices on food spoilage in pickled products, such as pickles, pears, and peaches, as well as the antibacterial properties of various spices.