To determine the sterility of ketchup, cultures were made from 77 of the bottles. The method used was to wipe the bottles and cork stoppers with a damp towel and then remove the cork. The cork puller which was used grasps the neck of the bottle in such a way as to cover the opening and remove the cork without the inrush of air that occurs when the ordinary corkscrew is used. A flame was then passed over the mouth of the bottle, after which the upper layer of ketchup was poured out, so as to discard any material which might have been contaminated in handling. Tomato gelatin was used as a medium and cultures were made in petri dishes. There were 17 plates on which no organisms developed, indicating that the ketchup was sterile. Of the 60 plates having organisms, 54 had molds, 22 of these having molds alone; 21 plates had yeast-like organisms, 3 plates having these only; 29 plates had bacteria, 4 having bacteria alone. Sometimes a plate would have only one form of organism, but more often there was a mixture present. Of 15 plates having only one form of organism, 3 had yeast alone, 2 bacteria alone, and 10 had mold alone. Of the 77 bottles of ketchup from which the inoculations were made, 41 were without and 36 with preservative, and of the 17 sterile ketchups, 8 contained sodium benzoate and 9 were without preservative. A considerable part of the experimental ketchup proved not to be sterile. The organisms present were of the class which require oxygen for their growth and therefore they had only been arrested in their activity. No growth could take place so long as the air was excluded and therefore no spoilage could occur. When the cork was drawn, the organisms could grow and cause spoilage, and this is a much more potent factor than the entrance of germs from without. Bottling and sealing the ketchup quickly while hot so completely excludes the air that only a few colonies of yeast or mold may be found on subsequent microscopical examination. Filling at a low temperature and corking while cool allows sufficient air to remain incorporated in the ketchup and neck of the bottle to permit a considerable growth of the organisms and a product derived from good stock may thus acquire the appearance of ketchup derived from partially decayed material. A ketchup in which bubbles of air are incorporated in filling may show a growth of mold at each bubble throughout the mass. The foregoing statements apply to ketchup containing sodium benzoate as well as to the non-preservative goods of the character used in these experiments. EXPERIMENTS WITH PRESERVATIVES. SODIUM BENZOATE. The preservative in general use in ketchup is sodium benzoate. Salicylic acid is used, but only to a limited extent. The amount of sodium benzoate used, according to the labels, varies from one-sixteenth to one-tenth of 1 per cent; but on some labels the amount is not stated. Experiments were made to determine the amount necessary to check the spoilage of ketchup.