-255 -Surface and deep electroencephalograms , electrocardiogram and behavior of 10 male rabbits were studied by infusing fresh water or sea water slowly at a speed of 0.5-2.0 ml/min, by means of a dripping apparatus, into the canulated trachea until the death of the animals.From the behavior of the animal and EEG and ECG findings, the course was divided into 4 stages. The 1st, alert stage; 2nd, adapted or calm stage; 3rd, dyspnea stage; and 4th, covering from the agonal spasm to ECG silence. The course of this drowning death was quite different from that due to a large amount of water aspirated within a short period. The volume of fresh water needed to kill the animals was 7 times larger than that of the sea water in this method, and the latter was less than half of the volume of sea water necessary for the death due to short period aspira tion. The mechanism of death seems to be slow and prolonged asphyxia and, among the terminal events in fresh water drowning, there might occur marked pulmonary hypertension that results in a high degree of lung edema.In the ECG at terminal stage, final bradycardia (84.4% of normal pulse rate) at around the time of surface EEG disappearance, and final tachycardia (142.7% of normal pulse rate) about 120 sec later than final bradycardia and 40 min later than deep EEG disappearance were observed consistently. After clinical signs of death ECG still continued to beat slowly for 1-2 hr.slowly induced sea and fresh water drowning; permanent electrode; EEG; ECG Since the first heart transplantation was performed in 1967 in our country, the donor-problem has been widely discussed all over Japan, not only from the medical but also from the ethical and moral aspects. One of the authors, as a surgeon, has experienced an operative death case in which continuous ECG tracing was taken for more than one hr after the clinical signs of death. But the courses of events around the time of death of living creatures were not clearly documented so as to be readily applied for the resuscitation and/or organ transplantation etc. by any physicians or surgeons.