K. LISSAK AND E. ENDROCZI 



297 



hormones with high pohirity was interpreted to increase the intensity of 

 the inhibitory processes. After the administration of ACTH, Mirsky, 

 Miller and Stein (1953), observed facilitation of the avoiding conditioned 

 reflex, which would seem to indicate that hypophysial-adrenocortical 

 activity supports the neural adaptation of the defensive mechanism. In 

 later experiments, however, it was observed that ACTH and the corti- 

 coids not only influence exteroceptive inhibitory and neurotic pheno- 



1 



tm 



Lady 



4 5 days 



Mexi 



12 3 4 



5 days 



Tigris 



days 



2- 



4 



Rex 



5 days 



Fig. 3 

 Fig. 3 shows that in certain cases the administration of ACTH increases inner inhibition 

 considerably. Development of inner inhibition on dogs. The ordinate corresponds to the 

 trials for each day. Blank columns: without treatment with ACTH; Black columns: after 

 administration ACTH for 4 days (2, lU/kg. Zn-Cortrophine, Organon). 



mena but also increase the inner inhibition which develops after a positive 

 stimulus administered without reinforcement every day until the condi- 

 tioned reaction disappeared. On the following days this extinction was 

 repeated until the conditioned stimulus elicited no response. In view of the 

 fact that the times of extinction observed after an interval of several 

 months were practically identical in the same animals, it was possible to 

 check the effect of the treatment with adrenocortical hormones. The 



