GENETIC TYPE AND THE ENDOCRINES 711 



position made it possible to form the two different types of 

 conditioned reflex. The shock did not destroy the food re- 

 action even when the two reactions were studied during 

 the same day. 



Complete hypophysectomy was performed, and the condi- 

 tioned reflex tests carried on for 2 months afterward. 



The results are clear cut. After the operation, the salivary 

 C-R disappeared entirely and the stronger motor C-R almost 

 entirely. Behavioral reactions outside the laboratory, includ- 

 ing reactions to food and to a shock, were not affected in 

 any observable way until a week or 10 days before the dog's 

 death from pituitary insufficiency. To all appearances the 

 animal was perfectly normal up until the terminal phase. 



After the operation, and during a period in which the 

 conditioned motor reflex alone was being observed, extracts 

 of the anterior and of the posterior pituitary lobes were 

 administered as a check on the results. General anterior 

 lobe extract (growth extract Squibb), 2 cc. daily, was given 

 subcutaneously for 6 days, and following this the dose was 

 combined with posterior lobe extract (pituitrin) % cc. daily 

 for 3 days (also given subcutaneously). The motor C-R alone 

 was tested at this time. Little, if any effect on behavior was 

 noticed during the administration of the extracts. 



Table 20 shows the post-operative changes in the two 

 conditioned reflexes. The efficiency of the salivary C-R dropped 

 from a high level (84 per cent) to zero, and the magnitude 

 of the response naturally decreased to zero (5 to 0). 



The efficiency of the motor C-R was also enormously de- 

 creased (100 per cent to 19 per cent) in the period just after 

 the operation. This was not improved very noticeably during 

 the administration of the anterior lobe extract, and an obvious 

 decrease was evident when the anterior and posterior lobe 

 substances were given together. In the terminal phase of 

 the experiment the motor reflex could not be elicited at all 

 (0 per cent). 



The magnitude of the motor C-R followed a similar course. 

 It declined strikingly in the first post-operative period (28 



