After a boiler explosion on a ship 12 men with cutaneous scalding of 90-100% of body surface were found dead. 15 other fatalities occured after different intervals. This investigation deals with the histomorphologic changes in those 12 cases of instantaneous death. The most important findings consisted of: 1. Thermal injuries of the skin with multiple subcutaneous and corial bubbles, intravascular heat coagulation, and edema in the transitional zone to the undamaged submucosa. 2. Coagulation necrosis of the tracheal and bronchial wall extending to alveolar ducts in central parts of the lung. Marked congestion and edema in the deeper layers of the mucosa. Hemorrhagic alveolar and interstitial edema of the lung. Striking congestion of the pleura parietalis saving up the recessus diaphragmaticus. 3. Acute nephron-nephrosis and periglomerular microangiopathy. Interstitial edema of the myocardium, degeneration of myofibrils. Acute vacuolar degeneration and swelling of hepatocytes. Phagocytosis of detritus by the RHS. 4. Swelling of endothelium and edema of the vascular walls. Intravascular fragments of erythrocytes, platelet aggregation and fibrin thrombi. The fatal cours in these cases is considered to be due to a fulminant shock syndrome.