J radiation, of course, damages any blood forming tis:ue n the direct field, At the present, ellfattempts to demonstrate ank Windtrect effect" peculiar to radiation on the bicod forming tissues hid foiled. However, the reduction jn white blood cells sometines found in man after treatment to local areas thought to contain but relatively little bloot-forming tissue remains poorlg understood. ‘The question requires further eritical study. Internal Radiaifion This invibves chiefly the use of radioisotepes and ditfers from other types of radiaiton chiefly in that relatively non~penetrating radidtions euch as alphg and beta rays can be introduced into the body where they may rediate tissues they could not reach by sxterrial application. This opens the possibility of giving radiation to tissuss without apnarently affectins others. Reacicactive iodine and redioootive nhesphorous are cxemples of substances thus empleyed. In gencral, the ao 4 2 ae , 2 $ + « ™. effaet o!n ridifosstive presphcivus int he 1? blocc-Sorging organs corresponds wiosely to PR ae? Lheatpnetw1, oS. seape ae ht . the offecte. attainable by externcl rodiatione The Tffect ofNeutror.s a The effects on the blooed-lorming tissu of H-rayee. spo essentially siziler to these Using fast neutrons, the biologic danare resulting from ln (erount of noire radieiton producing some amount of lonizatiog as lr H~radAstion in an Sattioun chamber) is about eight tines es great as thet resulting from lr. Effects of Radiation on Man Wv The purpose of all the dpe work revieved is to get a better idea of the effsct of rediation on gan. Acute exposures to sfnvle deess of whole body radiation mey occur in min, as aneccidient, or after detonation of an atoric bomybe are otherise seldom encountered, They In Ajividueds stodied in denen who wer: exposed to radiation at the time of the detonation of the bacb, the abnormalities in the blddd were found si:ilar to these experinentally in animals. The first ab- normality noted was reduction inthe numb:r of white blood cells, the second was re~ Anation fn hland nlstetate anil tha thiwnd ano wv Anat san fn we A RDAAD AAT.