HEMATOLOGIC EFFECTS OF RADIATION 



1033 



LD 50 these values may not reach the normal range for 30-90 days. 

 According to Bloom (1947), lymphatic tissue and lymphocyte production 

 after exposures in this range are qualitatively normal as judged by 

 histologic methods at 20-30 days. This discrepancy between the findings 

 in the peripheral blood and in the lymphatic tissue is understandable when 

 it is realized that histologic findings are admittedly qualitative. 



Table 16-1. Effect of Total-body X Irradiation and Exposure to Fast Neu- 

 trons on the Leukocyte Values of the Peripheral Blood of Rabbits 



Recovery not complete during 37 days of observation. 



Monocytes of the peripheral blood initially follow a pattern of response 

 similar to that of the lymphocytes but characteristically return to normal 

 values or show an absolute increase between the fourth and sixth days 

 after exposure of the animal to 100 r or above. No change of significance 

 has been observed in the number of plasma cells in the peripheral blood. 



The polymorphonuclear leukocyte, referred to as a heterophil in the 

 rabbit and a neutrophil in man, follows a somewhat different pattern than 

 does the lymphocyte after total-body irradiation. The most complete 

 data have been derived from observations on rabbits. The sensitivity of 

 the heterophil in mice, rats, rabbits, monkeys, and swine is, in general, 



