The results of our study may briefly be summarized as follows: 1) The irradiation with microrays (20∼30 watts) similar as 2,000 R and 5,000 R Gamma radiation did not substantially affect the activity of fibrinolysin
(SK+SD). 2) By the irradiation method so far mentioned it has been demonstrated that the fibrinolytic activity of anticoagulant of the SK+SD preparation is preserved in all the clotting systems which we used. 3) Our findings indicate that it is possible to irradiate patients for therapeutical purpose with Radarmed (electromagneticrays) provided that there is produced some enhancing influence of the same blood clotting factors or systems. Together with earlier works in this field it appears that this method of the microirradiation could provide us with an important evidence on which we can base our further in vitro and in vivo radiohematologic studies; investigations with various preparations, types of radiation that are still underway9∼16.</p