1058 RADIATION BIOLOGY 



returned to normal value in 41 days. The leukocyte values fell rapidly 

 during the first 4 days and then gradually disappeared completely from 

 the blood in 15 days, recovering slowly and only approaching normal 

 values at the end of 48 days. The same general pattern of peripheral- 

 blood changes was found by Warren following administration of 300 /ic to 

 19-day-old chicks and 760 /zc to 28-day-old chicks. The larger doses 

 caused a fatal anemia. 



Dixon (1948) injected chickens subcutaneously with 300 or 400 mc of 

 P 32 every week for three weeks. A virtual agranulocytosis and thrombo- 

 cytopenia developed by 7 days and remained thus during the period of 

 observation (17 days). Erythrocyte values decreased steadily reaching 

 0.5 million/cu mm by 17 days. 



Raper and Barnes (1951), Raper, Zirkle, and Barnes (1951), and Raper, 

 Henshaw, and Snider (1951) studied total-surface radiation with (5 rays 

 in rabbits. With doses ranging from 1500-59,000 rep, no direct effect on 

 the cellular constituents of the peripheral blood was noted. Sporadic 

 increase in the heterophils began three weeks after irradiation with 

 10,000-15,000 rep, but no evidence of individual effect on the leukocyte 

 values was detected, nor was there evidence to substantiate the claim of 

 lymphocyte stimulation by superficial irradiation. The lack of effect is 

 considered to be consistent with physical properties of radiation and 

 anatomical features of the rabbit. 



SODIUM (Na 24 ) 



A moderate-to-severe leukopenia and lymphopenia followed injection 

 of radiosodium (Na 24 ) given intraperitoneally to mice in doses of 23-96 

 juc/g of body weight. With doses of 48-95 /xc/g of body weight, death of 

 the animals occurred by 8 days (Jacobson and Simmons, 1946a). 



BARIUM-LANTHANUM (Ba-La 14 °) 



A dose of 1.9 /xc/g of body weight administered intraperitoneally to 

 mice produced a significant and rapid reduction of leukocyte, lymphocyte, 

 and heterophil values that was sustained for approximately 60 days. 

 Rapid reduction in these values and death within 15 days followed the 

 administration of 17 juc/g of body weight. No significant change 

 occurred in erythrocyte or hemoglobin values by 60 days with these 

 doses (Jacobson, 1946). The radiation effects of these two isotopes in 

 the mouse may be entirely due to /3 rays (Finkle, Snyder, and Tompkins, 

 1946), although both and 7 rays are emitted. 



YTTRIUM (Y 91 ) 



Yttrium (Y 91 ) administered by gavage to rats in a single dose of 

 20 Mc/g of body weight produced a marked initial elevation in the erythro- 



