718 O. D. ANDERSON 



times during the ensuing period of 10 months. Marked im- 

 provement in general behavior was noted about 10 days or 

 2 weeks after each transplant, an improvement so striking 

 that the dog appeared almost normal. This lasted about 1 

 month, after which a noticeable decline set in, and approxi- 

 mately 3 months after the transplant the dog was again in 

 a lowered condition, but not so low as before this form of 

 treatment was tried. At this time another transplant was 

 given and the cycle was repeated. 



To facilitate tabulation of the results in table 21, the 10 

 month period, during which the three transplants were tried, 

 is treated as a single unit. 



TABLE 21 



Bog C-l $ 



AFTER HYPOPHYSECTOMT 



TRAINING 

 PERIOD 



Correct responses to positive 



Met. 120 86% 



Correct responses to negative 



Met. 28 33% 



Average magnitude of C-E to 



positive Met. 120 9 



During Durinc During 



No anterior ^"w Penod of 



extract pituitary pv > rart pituitary 



extract exlracl transplants 



20% 40% ; 58% 25% 



80% 80% ! 100% 



1—3 3 2 



It can be seen from table 21 that the normally stable C-R 

 was greatly diminished in efficiency after the operation (86 

 per cent to 20 per cent), was increased during the anterior 

 pituitary extract (to 40 per cent), was further increased 

 during thyroid administration (to 58 per cent), but dimin- 

 ished on the whole and was maintained at a diminished level 

 during the period of pituitary transplants (25 per cent). 

 The efficiency of response to the negative Met. 28 was con- 

 siderably increased after the operation (33 per cent to 80 

 per cent), remained at that level during the anterior pituitary 

 extract, but was augmented during the administration of 

 thyroid substance (100 per cent). Tests of the negative re- 

 sponse were discontinued during the transplant period. 



