EFFECTS OF RADIATION ON CNS AND ON BEHAVIOR 



635 



failed to pull any rabbits out of hats with this design, and we succeeded in 

 controlling all variables so eflectively that the monkeys seldom looked out 

 the windows. There were no data, and consequently no differences. Our next 

 step will be to test visual exploratory behavior when the modified Butler box 

 is attached to the animal's home cage and the testing conducted after an 

 assigned number of hours of visual deprivation. 



An attempted stress test without electric shock is shown in Fig. 10. This 

 is a smooth-walled Plexiglas and metal chamber with a steel pole in the 

 center and 4 in. of cold water in the pan at the base. The monkey was 

 introduced to the test through a door at the back of the chamber, and each 

 session lasted 15 minutes. 



The data on the 50 r group are somewhat less than spectacular. The 

 normal monkeys spent less time out of the water than those irradiated (Fig. 

 11). Some monkeys learned ways to brace themselves between the pole and 

 the wall of the chamber, thus avoiding the water, and two control animals 

 made little or no attempt to keep out of the water. We plan to modify the 

 apparatus by making walls with no interior projections and by making the 

 water so deep that the monkeys must either hold to the pole, swim, or drown. 



Actually, even the unmodified situation may give us effective predictors 

 of approaching radiation death, since the cold water appears to be a more 

 noxious stimulus for irradiated animals than for the controls, and the single 

 one of the 12 irradiated monkeys that has died evinced a sharp decrease in 

 time on the pole as death approached. 



Figure 12 depicts a general activity test in which movements in the home 



Fig. 10. Stress test apparatus. 



