The injuries from total body exposures to ionizing irradiationare multiple in nature and different in kind, and thus the spectrum of effective treatment is broad and difficult to achieve. While burns, penetrating and open wounds and fractures constitute the majority of the immediate casualties of atomic disaster, their treatment is conditioned by the fact that the systemic pattern of events which appears during the ensuing six weeks may be more serious than the initial local trauma. These latent sequelae constitute the postirradiation syndrome, which is characterized primarily by hemorrhage, infection, anemia and malnutrition. Since the experimental approach must be employed, the dog was chosen as the animal of study, as nearly all the signs exhibited by the victims of Hiroshima and Nagasaki can be observed in the roentgen-irradiated dog. The L.D.100for the dog ranges between 300 and 325 r under the experimental conditions employed by this laboratory and