500 BIOLOGICAL EFFECTS OF RADIATION 



output for 2 weeks after exposure. One animal returned to normal 

 47 days after exposure. They conclude that the pancreas may be 

 temporarily injured by one erythema dose, its power to regenerate being 

 able to compensate for this. 



Liver. — There is a controversy concerning the effects of roentgen and 

 gamma radiations on the liver. Many investigators find no evidence 

 of histological change (134, 207-209, 291, 369-377), while others 

 report injuries of various kinds. Pohle and Bunting (277) describe 

 swelling and atrophy of the cells, a reaction which occurs in two cycles, 

 somew^hat similar to the rhythm noted in the skin erythema. In some 

 instances (83) the liver may be reduced in weight and show extensive 

 fatty infiltration, some increase of fibrous tissue, and a loss of orderly cell 

 arrangement. Three human cases (38) showed injury to the bile ducts, 

 with vacuolation, swelling, and necrosis of the epithelial cells, followed 

 by a slow and atypical regeneration. Hartock and Israeleski (138) 

 review the literature on this subject, and present evidence showing that 

 the secretion of bile in the frog is diminished by doses of 500 r or more. 

 The effect lasts at least 3 weeks. Russ and Scott (310, 312) implanted 

 radon seeds in the liver of a rat and found that those cells which were 

 intensely irradiated were less injured than those which received less 

 radiation. Furthermore, cells near the blood vessels were less injured 

 than those at some distance. Chronic changes in the liver are rarely 

 observed because either the subject succumbs to massive destruction 

 from large doses, or the regeneration after smaller doses is so rapid and 

 complete as to leave little or no residual (59, 83). 



The nuclear damage which has been reported (204) may not be a 

 consequence of irradiation. The livers of rats and rabbits kept under 

 laboratory conditions are apt to show occasional pathological variations; 

 furthermore the dosage used is comparable to that used by others who 

 found no histological changes under similar experimental conditions. 

 There is no doubt that transient anatomical or histological and functional 

 damage may be produced by radiation (83). The best evidence of 

 functional effects is presented by means of bile fistula experiments (337) . 

 There is considerable evidence of rapid recovery of the liver function. 

 But if sufficient radiation is given repeatedly, in the proper sequence and 

 dosage, extensive irreparable damage might be obtained. A compre- 

 hensive, well correlated study of the effects of roentgen rays on the liver 

 is needed. 



Gall Bladder. — Brahms and Dornbacher (27) in irradiating the liver 

 region of the dogs with relatively soft irradiation (65 kv.) found both acute 

 and chronic changes in the gall-bladder wall consisting of hemorrhage, 

 edema, round-cell infiltration, fibrous-tissue hyperplasia, and occasion- 

 ally necrosis of the epithelium. These lesions were obtained without 

 damage to the duodenal and pyloric mucosa, and they suggest that the 



