NEUTRON EFFECIS ON ANIMALS 



147 



following administration of the test meal. However, after this time the 

 digestive activity of the gastric fluid of the irradiated rats was much less 

 than that of the controls (Fig. 5) until at the end of 4 hours they were 

 approximately the same. 



Comment. In normal rats food consumption initiates a series of activi- 

 ties associated with gastric digestion: secretion of digestive juices, active 

 gastric peristalsis, some protein digestion and expulsion of food through 

 the pylorus. In the irradiated rats the food remained longer in the stom- 

 ach; there was a slightly greater amount of fluid, a reduced total acidity, 

 a higher pH of the fluid and a reduced digestive ability. 



HOURS 



Fig. 5. The effect of 56.4 n on the peptic activity of the gastric juice of rats, 

 radiated. O Control. 



The factors initiating these abnormal changes after neutron irradiation 

 are not known. It is conceivable that such factors as reduced muscular 

 activity of the stomach, spasm of the pylorus, and changes in the chemical, 

 enzymatic and nervous systems contribute to, or are responsible for, the 

 delayed expulsion of food from the stomach. This retention then may be 

 responsible for the reduced food intake of irradiated animals. 



INFLUENCE OF AGE, WEIGHT AND STATE OF NUTRITION ON RESPONSE TO 



NEUTRON IRRADIATION 



In the course of investigations concerning the effects of neutron radiation 

 on rats, it appeared that older rats withstood exposure to neutrons with less 

 severe effects than younger ones. Further observations concerning this 



