The pathological changes of blood circulatory disturbances of the rat lungs induced by blast or blast burn injuries were analysed quantitatively by quantimet 920. After infusion fixation with 40% formalin, the different relevant grey levels were viewed in four longitudinal sections of left and right lungs. The different greg levels corresponded with the severity of circulatory disturbancecs, espesially with the hemorrhage. Because various degrees of disturbances play different roles in the pathophysiological effect on the body, weight coefficinet 0, 1, 2, 4 were designed respectively according to the grey level, the sum of both all grey area of the lung and corresponding weight coefficinet indicates the value of the degree of circulatory disorder in the injuried lung. Thus the severity of the pathlogical changes could be estimated quantitatively.

Seven hundred and forty-six mice, weighing 30-35 grams, were divided into four groups randomly. The animals of the first three groups were inflicted with radiation injury (12 Gy total body irradiation from a Co60 source) , burn injury (15% of third degree burns), and combined injury of radiation and burns(12 Gy total body irradiation and 15% of third degree burns) respectively. The fourth group worked as normal control.The mortality and the dynamic changes of the intestinal epithelium of the experimental animals were studied. It was found that the clinical course of the combined injury group was quite different from other two. The mortality of the combined injury group was higher and the damage on the intestinal epithelium was more severe than those of the radiation injury group in the first 48 hours after injury. In the second 48 hours, the mortality of the combined injury group became lower and the recovery of the intestinal epithelium faster.The reactions of the experimental animals to the combined injury of radiation and burn were-very complicate. Further investigation is essential to elucidate the mechanism and to formulate appropriate therapeutic measures.