970 RADIATION BIOLOGY 



cell volume has been attributed to the failure of erythropoiesis, destruc- 

 tion of the mature cells, and internal bleeding. Cell and plasma volumes 

 have been determined in mice, rats, rabbits, and dogs, using P 32 tagged 

 erythrocytes, iodinated plasma proteins, and the conventional Evans 

 blue technique. Following irradiation of the rabbit with 1000 r, there is 

 a parallel decline in cell and plasma volumes that begins on the third 

 day. By the tenth day, however, plasma volume rises, reaching a level 

 some 10 per cent above the normal during the third week when the red 

 cell volume is decreased by more than 40 per cent (Storey et al, 1950). 

 The blood volume is, therefore, only slightly diminished. In the irradi- 

 ated dog, plasma volume may be increased by more than 50 per cent when 

 the red cell volume and hematocrit are severely depressed (Soberman 

 et al., 1951). Rather similar findings have been observed in mice and 

 rats (Storey et al., 1950; France, 1946). Although there is some disagree- 

 ment in regard to the early decline in plasma volume, this may be attrib- 

 uted in some instances to whether the volume is expressed as a percentage 

 of the preirradiation body weight or of the body weight at the time of 

 determination (Storey et al., 1950; France, 1946). The rapidly falling 

 blood pressure that is seen frequently in rabbits during the first hours 

 after irradiation is not accompanied by significant changes in blood 

 volume (Painter et al., 1947). 



When massive dosages are applied to the abdomen or whole body of 

 the dog, death nearly always occurs during the first few days with hemo- 

 concentration (Moon et al., 1941). With less severe, but nevertheless 

 lethal, exposure to X radiation or after injection of Sr 89 or Pu 239 , the 

 usual rise in plasma volume is seen during the intermediate and acute 

 periods as the red cell loss becomes appreciable (Prosser, Painter, Lisco, 

 et al., 1947). Thus, as contrasted with traumatic shock, hemoconcentra- 

 tion and appreciable diminution of blood volume are not observed in the 

 irradiated animal unless the radiation dosage is well above the minimal 



LUioo- 



There is no information concerning the blood volume after superficial 

 irradiation, e.g., with rays. A decrease in blood volume would perhaps 

 be anticipated because of plasma loss in the burned areas. It is possible, 

 however, that plasma loss might occur so slowly that compensatory 

 mechanisms, e.g., shift in fluids from other compartments or water 

 retention, could operate to prevent a change in blood volume. Similar 

 information is also lacking for neutron irradiation ; it is probable that the 

 effects with neutrons would resemble those seen after X irradiation. 



Lymph and Tissue Fluid. The output of lymph from the thoracic duct 

 of cats is unchanged during the first hours after 1500 r X irradiation of 

 the whole body (Valentine et al., 1948). Lymph flow, as visualized by 

 thorotrast, is not affected following localized X irradiation of the hind 

 legs of rats (Hodes and Griffith, 1941). The volume of cutaneous lymph 



