Although glutaraldehyde solution was injected into the superior mesenteric artery, vessels and blood cells were not fixed immediately. 2) Glutaraldehyde was considered not to be suitable for the fixation of vessels and blood cells. 3) To observe the physiological and topographical correlation of vessels and blood contents, drop osmium fixation method was better to fix the microcirculatory units immediately. 4) The perfusion of glutaraldehyde was supposed to be necessary for the fixation of the solid tissue in which microcirculatory systems exist in deeper places like liver. However, the findings observed by the perfusion method might reflex microcirculatory disturbances occured by the perfusion of glutaraldehyde itself.