The severe toxicity was observed when rats were given the diets containing 10 per cent cyclic monomer and it was difficult to observe the histological changes since all rats died in 4 or 7 days. Then a small amount (2.05-7.5 per cent) of cyclic momomer was given to rats and after 38 days the changes in rat's livers and cerebrums were observed by microscope. As the results, cyclic monomer gave severe toxicity to the rat liver and cerebrum; the liver was considerably enlarged and the adipose spots were clearly seen with the naked eyes. And also in microscopic observation, also, the necrosis of liver cells was remarkably observed by microscope. In cerebrum, Cerebral edema was found in all over the cerebrum and deficiency or degeneration of nerve cells and congestion of the tissue were observed there.
Ume-shu (Japanese plum liqueur) was prepared by the conventional method in this study. Nonvolatile organic acids of Ume-shu were separated by ion-exchange chromatography. Analysis of the acids after butylation by gas chromatography led to the detection of eight components, two of which were benzoic and succinic acids not reported hitherto in Ume-shu.