492 BIOLOGICAL EFFECTS OF RADIATION 



tissues, skin, etc. The amount of damage is always proportional to the 

 dosage plus the sensitivity of the cells involved. 



Tsuzuki (354) finds a great many acute changes in most of the organs 

 when the whole body of the rabbit was irradiated, and the animal sacri- 

 ficed directly after irradiation or at intervals of 3, 13, 36 hr. All of the 

 organs, including the salivary gland, thyroid, lung, thymus, heart, liver, 

 spleen, intestines, pancreas, kidney, adrenal, testis, and bone marrow, 

 showed hyperemia and apparently some degeneration of cells. Much 

 of this is gone after 36 hr. with a residual of a slight amount of atrophy. 



He explained the onset of the acute intoxication which he noted 

 following such irradiation upon the basis of this rather extensive acute 

 cell destruction. The latter was quickly followed by repair. Some 

 of the changes described may not be due to the irradiation, but this 

 phase should be further studied. The dosage used and the period of 

 observation were probably well below those necessary to enable the 

 author to study the acute syndromes mentioned above. 



Exposure of the entire body to a large quantity of radium may bring 

 about very similar damage, i.e., destruction of lymphoid tissue in the 

 spleen, lymph nodes, intestinal lymph follicles, and bone marrow, degen- 

 eration of the epithelium and hyperemia of the intestine, cellular 

 degeneration in the testis or ovary, stomach and intestine, kidneys and 

 liver, mucoid degeneration and desquamation of the columnar epi- 

 thelium of the bronchi and trachea, hyperemia, alveolar exudation, and 

 focal consolidation of the lungs (73, 74). 



Intravenous or oral administration of sufficient doses of thorium X 

 or radium salts or emanation induces a leucopenia affecting chiefly the 

 lymphocytes, large mononuclear cells, and blood platelets, hyperemia and 

 hemorrhage of the bone marrow, marked destruction of lymphocytes and 

 atrophy of lymphoid follicles in the spleen and lymph nodes, inflamma- 

 tion and destruction of the vascular endothelium, with secondary 

 proliferative thickening of the vessel walls, central parenchymatous 

 necrosis of the lobules of the liver, hyperemia, exudative distention of the 

 glomerular capsules and coagulation necrosis of the kidneys, and intense 

 hyperemia of the lungs, with exudative distention of the alveoli. After 

 intravenous injection, the greatest changes appear to be in the blood 

 vessels, lymphoid structures, and liver, whereas, after oral ingestion, the 

 large intestine, lymphoid structures, and kidneys suffer the greatest 

 injury (73, 74, 185, 188, 193, 201). 



These effects differ little from those brought about by intensive 

 roentgen irradiation. The chief difference lies in the low intensity of 

 radiation spread over a very long time interval. The fact that the 

 intestine, kidney, and lung are sites for excretion while endothelial 

 phagocytes, bone, liver, and spleen are sites for storage of any particu- 

 lar foreign material would tend to intensify the damage in such structures. 



