Abstract
A slowly growing solid sarcoma was implanted subcutaneously on the anterior chest wall of mice. On reaching a predetermined size the tumours were locally irradiated using 240 kV x-rays with single doses of 0, 2000 or 5000 rad. The mice were sacrificed 12 weeks after irradiation and examined for lung metastases, which were found to be less frequent in those mice whose implanted tumours had received the most irradiation.