The time required for the ketchup to spoil was longer than in the first set, but there was not sufficient difference nor enough uniformity in the time to indicate that the use of oil in ketchup is desirable, even if the change of flavor and odor be not taken into consideration. The average number of days before spoilage for those containing 1 part of oil to 500 parts of ketchup, was thirteen and two-thirds days; one has not yet spoiled (a period of forty-five days), while the first bottle spoiled in four days. Those having 1 part of oil to 400 parts of ketchup had an average life of nine and three-fourths days, the minimum being three days, and the maximum twenty-six days. Those having 1 part to 300 parts of ketchup on an average did not spoil for six and three-fourths days, the minimum being four days, and the maximum eleven days. The failure of some of the bottles to spoil, though similar in every known respect to those which did spoil, is a feature peculiar to ketchup and is familiar to manufacturers who make careful tests before putting their product on the market. For this reason a rather large number of bottles should be used in a test in order that the results may be approximately accurate and represent general conditions. STUDY OF PENICILLIUM IN KETCHUP. Penicillium is a plant which is distributed widely and apparently is able to grow wherever organic matter is found, though flourishing best when the material contains acid. It causes loss in canneries, breweries, distilleries, etc., the only use made of it being in the manufacture of Roquefort cheese, the immature cheese being inoculated with the conidia for the effect the mold produces in the maturing process. [Illustration: Fig. 1.--Conidia, Normal Size and in Various Stages of Germination, Some with Branching Hyphæ (× 325).] [Illustration: Fig. 2.--Conidiophore, Showing Unusually Large Development of Conidia, from Culture in Moist Chamber (× 325).] PENICILLIUM. [Illustration: Fig. 1.--Conidia and Hyphæ from Culture in Experimental Ketchup Containing One-sixteenth of One Per Cent of Sodium Benzoate (X 325).] [Illustration: Fig. 2.--Conidia and Hyphæ from Cultures in Experimental Ketchup Containing One-tenth of One Per Cent of Sodium Benzoate (X 325).] CULTURES FROM KETCHUP PRESERVED WITH SODIUM BENZOATE. DEVELOPMENT.