704 O. D. ANDERSON 



cent to 75 per cent) but was returned completely to normal 

 during the administration of parathormone (100 per cent). 

 The efficiency of the response dropped back to about the 

 pre-injection level after the extract was withdrawn (66 per 

 cent). The percentage of correctness of the negative C-R 

 increased after the operation (38 per cent to 50 per cent), 

 decreased during the extract period (to 20 per cent) and 

 increased in the after period to about the previous level (44 

 per cent). 



The average magnitude of the C-R was changed enormously 

 after the operation, being reduced more than five times (45 

 to 8). This was increased notably during the administration 

 of the extract (to 24) although the normal level was not 

 attained. After the substance was withheld, the value dropped 

 to approximately the same level (6) as before the parathor- 

 mone was given. 



The detailed data are presented in graphic form in plate 

 110 (figs. 1-4) and text-figure 125. In plate 110 graphic 

 records of the motor reactions of this dog during the normal 

 control period are shown. The graphs are described begin- 



PLATE 110 



EXPLANATION OP FIGURES 



1 The fairly calm and deliberate reactions of animal 856 before attempts 

 to form a differentiation between positive and negative stimuli. 



2 and 3 The extreme state of nervousness produced in this dog (856) following 

 attempts to form discrimination between Met. 120 and Met. 42. The animal not 

 only reacts to both positive and negative stimuli, but also reacts when not being 

 stimulated at all. The head and body movements, respiration, and leg movements 

 illustrate the extent of the nervousness. 



4 The effects of removing the thyroid and parathyroids on the nervous be- 

 havior and conditioned reflexes in animal 856. Note the greatly diminished 

 reaction of the right forelimb to the Met. 120 and to the shock. Note also 

 that interval movements of head, body and reaction leg have practically disap- 

 peared. 



5 Graphic record of the conditioned salivary reflex in dog 492 prior to hypo- 

 physectomy. Note the alert head movement and vigorous conditioned salivary 

 flow to the Met. 120 followed by food. 



6 Graphic record showing the absence of the conditioned salivary reflex in 

 the same dog (492) following complete hypophysectomy. Food itself evoked 

 vigorous reactions of the head, body, respiration and salivation. 



