Abstract: This article was written aftern experimenting with 20 healthy white mice.Compared with the 5 normal mice and the other that received craniocerebral injury,drowning and straugulation,those injury showed some difference under the electromicroscope,though little difference was found between them in gross appearence and microscopic picture. In the 5 of craniocerebral injury,the obvious cleft of barement mem. branes of capillary and platelet agglutination on vasculum can be seen. The special features of 5 of drowning were edema of alveolar epithelium mictochondrial swelling,disruptious of plasma membranes of cell,nucl. ear chromatolysis and hemolysis.The 5 of straugulationwere charact. erized by large vacuolar swelling of endotheliaI cell and alveolar septal edema.