The histological studies were made on the spleen, manily the blood vessel system, in violent hepatitis, severe acute hepatitis, chronic hepatitis, livercirrhosis and Banti's disease. And the results were as follows. 1. As for the histological findings of the spleen in violent hepatitis and severe acute hepatitis, the serous exudation and tissue's melting changes were cheifly observed. 2. As for the splenic changes in Banti's disease, the sclerotic change of the connective tissue of blood vessel was mainly observed, and the disturbance of blood vessel was in the firest meaning. 3. The clinical and pathohitological findings of splenomegalic chronic hepatitis showed the transitional picture between hepatitis and Banti's disease and it was thought that splenomegalic chronic hepatitis played an intermediate part of them. 4. No essential difference between Banti's disease and livercirrhosis was observed, and it was thought that livercirrhosis was occured, if the secondary organic sclerosis originated in the disturbance of blood vessel was strong in the liver, and Banti's disease was occured, if it was strong in the spleen.