684 



(). I). ANDERSON 



This dog was a brother of 869, used in the preceding ex- 

 periment, and the behavior of the two animals was strikingly 

 similar. No. 864 was very active and muscularly powerful. 

 He was friendly and alert, and showed no trace of shyness 

 under any circumstances. 



The salivary C-R was formed at the sixteenth trial and 

 was relatively constant. 



#9U 



EFFECT of Partial THyRoiDECToriy 



ON THE CONDITIONED MOTOR REFLEX 



# t* 



% Mon* /is 



oV R M /) L I PARTIALLY THYROIDECTOMIZED 



Text -figure 122. Chart showing the effect of partial thyroidectomy on the 

 conditioned motor reflex in dog 869. Note the complete collapse of the reflex 

 following the operation and the gradual return of the reflex during the three 

 ensuing months. This return may be associated with the regeneration of the 

 remaining portion of the gland. 



As in the previous case, a partial thyroidectomy was per- 

 formed. A minute piece of thyroid tissue of the left lobe 

 remained, together with the corresponding external para- 

 thyroid. 



When the tests of the salivary C-R were resumed, follow- 

 ing the operation, it was found that this reflex had disap- 

 peared, as had the motor C-R in 869. Again, within almost 

 exactly the same time (3 months) the response gradually re- 



