As stated in Part I, the writer has found the difference of the water content among various kinds of brain edema. Therefore, the minerals in the cortex were investigated. For the measurement of natrium (Na) and potassium (K), Rourke iodine method and Kramer-Tisdall oxydation method were used after wet ashing. For chlorine (Cl), the extract of the cortex with saturated picric acid was investigated with the method described by Schales and Schales. In the cases of brain edema of edematous type caused by ligation of the bilateral jugular veins, injection of destilled water into the carotid artery and experimental commotio cerebri, Na and Cl increased and K decreased. The increase of Na and Cl was most striking in those with injection of destilled water into the carotid artery, then in those with commotio cerebri, and less in those with ligation of the jugular veins. Thus the change of Na and Cl was parallel to that of the water content. The decrease of K was most striking in those with ligation of the jugular veins and injection of destilled water into the carotid artery, and less in those with commotio cerebri, thus inverse to the change of the water content. All of Na, Cl and K decreased in the cases of brain edema of swelling type caused by irrigation of warm physiologic saline solution upon the surface of brain. In the cases with experimental chronic internal hydrocephalus, there was almost no change of Na, Cl and K.