14 



O. I). ANDERSON 

 PLATE 111 



1 A graphic record showing the conditioned motor reflex in dog 492 prior 

 to hypophysectomy. The response involves vigorous head, respiratory and re- 

 action leg movements to a pure tone followed by a shock. 



2 A graphic record showing the absence of the reaction leg component of 

 the conditioned motor reflex in the same dog (492) following complete hypo- 

 physectomy. Note that although the leg movement disappeared, the conditioned 

 head and respiratory effects remain. 



3 A graphic record showing the conditioned salivary reflex in dog C-l prior 

 to complete hypophysectomy. The head, respiratory and salivary reactions to 

 Met. 120 are vigorous. 



4 Graphic record showing the absence of the entire salivary reaction complex 

 in the same animal (C-l) following complete hypophysectomy. 



5 Graphic record showing the return of the salivary reaction complex in 

 dog C-l after the administration of thyroid extract. 



