1) The main postmortal autolytic changes were melting or agglutination of the fine granules, swelling and contraction of the cells. 2) The specimen for electron microscope should be fixed early as possible. 3) The fine structures were preserved relatively well within 2 hours after death. Therefore the specimens obtained within 2 postmortal hours could be used satisfactorily for the electron microscope. If unavoidable, the specimens obtained until 5 postmortal hours could be used, but the investigation of the fine changes might be difficult. 5) The specimens over 5 hours could not be used for electron microscope.