After a single or successive intramuscular injections of the patients with so-called Banti's disease into albino rats the author observed the adrenal cortical function hourly or daily and obtained the following results. 1. The number of peripheral erythrocytes was markedly decreased in both those given a single and those given the successive injections. This fact proves the existence of anemia inducing factor in the sera of so-called Banti's disease. 2. A fall in the adrenal cortical reserve funetion can be recognized after the successive injection. 3. There can be recognized no fixed tendency in the change of Na, K, Cl, Na/K in the serum. 4. The weight of the adrenal gland shows a slight decrease after the successive injections. 5. The total ascorbic acid of adrenals decreases after the single injection, while on the contrary, it increaaes markedly by degrees in the successive injections. 6. Histochemically in the case of the single injection, lipid granules of the adrenal cortex decrease in number and grow finer in the fascicular zone, while in the successive injections they become grosser and reticular in the fascicular and glcmerular zones. 7. The histological picture of the adrenal cortex in the successive injections reveals the swelling of the capsule and of the glomerular zone, hyperemia and the regressive changes in the nuclei and protoplalma in the reticular zone, but hardly any change can be observed in the fascicular zone. 8. From these findings it seems that the adrenal cortical function is acclerated in the case of the single injection, while the function is decreased in the successive injections. And these changes are definitely caused by anemia producing factor in the sera of patients with so-called Banit's disease.