Rats were fed with the diet of various fats for two months and the effect on their serum cholesterol was studied. When the ratio of oleic acid to linoleic acid in diet was 1: 1, and if the saturated acid was about one third of the total fat, the serum cholestelol was not increased. When the ratio was 2: 1 or 4: 1, and if the saturated acid was respectively less than one fourth and one fifth, the serum cholesterol was not increased. When the rats' depot fat composed with corn oil and soybean oil with the ratio of. 1: 1 was fed, the increase of serum cholesterol was not observed. When the rats' depot fat composed with olive oil, coconut oil, and fat free diet with the oleic acidlinoleic acid ratio of 4: 1 was fed, the increase of serum cholesterol was observed.
Effect of ultraviolet rayradiation in the refrigerator was investigated. Two refrigerators of the same type were prepared; one irradiated by a 2-watt lamp of ultraviolet rays inside and the other nonirradiated as a control. Suspensions of a certain concentration of bacilli such as Escherichia coli, Enteritis vibrio parahemolitics, Enteritis Gärtner, Staphylococcus and hay were put and left in the two refrigerators. After a certain hours' storage, the number of colonies was examined. It was found that in the irradiated samples it was reduced to 1/6-1/300, possibly influenced by ultraviolet rays. Farther, to study a preservative value of ultraviolet rays acting against putrefaction, pH, NH3 production, protein precipitation, the number of all bacilli per 1g were compared. The results showed the progress of putrefaction in the irradiated samples was 5-6 days slower than in the control non-irradiated, and that the number of bacilli in the air in the refrigerator irradiated decreased, to 1/6. The air contained only a small amount of ozone.