For the purpose to learn the relation between the catalase activity of liver and the disease the author performed the estimation of catalase activity in the liver from the autopsy materials. Prior to perform the estimation on the autopsy materials the changes in the activity of the enzyme after the death have been checked on rats with a certain period of time after killing the animals. The tests proved that no change occurs in the activity in those preserved at 1 to 2 C in a ice chamber 24 hours after the death, though a marked decrease can be seen after 17 hours at 37 C. On the basis of this observation all the autopsy materials are taken within 8 hours after the death. As the results it has been found that the liver catalase decreases markedly in its activity in some disease as revealed by estimating with the slightly modified method of Bonichsen, Chance and Theorell. The liver tissues from 5 cases bearing malignant neoplasms and having tumors in the liver show a markedly low activity in catalase, 65.7% of the normal level in mean value, and the tumor tissues themselves in the liver are found to be extremely low in activity, 27.5%. A relatively low activity also can be seen in the liver from another tumor-bearing individuals, in which no metastasized tumor in the liver has been found, 82% of the normal level. With one exception of lymphosarcomatosis, where the activity have been found to be 1/10 of the normal level, in four cases of leukemia (2 monocytic leukemias and 2 lymphocytic lekemias) the activity has been found to be 64.8% of normal level. In four cases such as uremia, nephroses and so on, in which the metabolic activity is supposed to be lowered, relatively low levels have been found in the activity of liver catalase (82.5% in mean value).
In 8 cases died of hemorrhage, benign tumor in brain and others the catalase activity of liver are kept almost at normal level. These observations show that the lowered catalase activity in liver does not necessarily be accompanied by the tumor formation.