NEUTKON EFFECTS ON ANIMALS 39 



of the observed results will have to await the accumulation of additional 

 data. 



Neutron Doses of 17. o n to 240 n. The primary purpose of this phase 

 of the experimental work was to determine the general relationship between 

 the general effects on rats and the specific effects on the blood as produced 

 by varying doses of neutrons. 



The results indicate that with neutron doses of 180 n and 240 n death 

 occurs in from 6 to 8 days with little or no difference between the two doses. 

 These acute deaths are characterized by a continuous loss in weight and 

 extreme leukopenia. The changes in body weight are very striking and 

 death occurred at a point when the loss in weight was equivalent to 20 to 

 30 per cent of the initial weight. The rats were not observed to eat any 

 food after the first dose of neutrons. A weight loss for any one rat exceed- 

 ing 15 per cent of the initial weight together with complete loss of appetite 

 and acute diarrhea followed by a mucous discharge may be considered as 

 definite signs of an irreversible reaction which will terminate in death. 



Since these animals showed a general appearance of acute starvation, 

 a group of rats was deprived of food so that a picture of starvation could be 

 obtained for comparison with that produced by irradiation. In these 

 starved animals, a weight loss of 35.4 per cent was observed at the end of 

 10 days with the death of only one of twelve rats. The survivors when 

 again given access to food regained their initial weight within two weeks. 

 The rate of loss of weight was practically identical for both the starved, 

 non-irradiated animals and the irradiated animals (180 n and 240 n). 

 In fact, the only observable difference between these two groups was that 

 only one of the starved animals died in 10 days while all of the irradiated 

 ones were dead in 7 to 8 days. Apparently in irradiated animals some 

 mechanism of the digestive system is disturbed if not completely inhibited. 

 From autopsy evidence, a pyloric spasm may have occurred inhibiting the 

 passage of food from the stomach to the duodenum. In addition, some 

 action on the gastric enzymes may be assumed on the basis of the partially 

 digested condition of the food found in the stomach at autopsy. At high 

 neutron doses, the pyloric spasm might be considered as complete and 

 irreversible and death as being due, at least in some degree, to starvation 

 and the resulting tissue destruction. These data support the conclusion 

 of Lawrence and Tennant (5) that tissue destruction plays an important 

 part in the mechanism of acute action of neutrons. It would be interesting 

 to see if such animals could be saved or their life prolonged either by forced 

 feeding with duodenal tube or by intravenous feeding with predigested 

 proteins. Such experiments might show that other effects of neutrons 

 have been produced \\hi('h are masked by the rapid and fatal progress of 

 starvation. 



