GENETIC TYPE AND THE ENDOCEINES 551 



animal is unable to form conditioned reactions to such stimuli. 

 Under other conditions this animal is able to form both tactile 

 and visual conditioned reactions. It must be remembered 

 that these signals were not introduced until the animal had 

 progressed in the performance of food taking", and had al- 

 ready begun to consider the rotation of the disk and the food 

 as the significant factor. Since the same effector was em- 

 ployed with the tactile and visual stimuli as with the auditory 

 signal, no further adjustment was required. Since no other 

 effector was employed, the animal was not aroused to action 

 but remained in a state of general inhibition. The dog did 

 not become active when the new signals were introduced; 

 this performance begins where the other ended. 



A second dog of this group, 219 $ , formed a weak condi- 

 tioned reaction to tactile and visual stimuli. When the new 

 stimuli were introduced, however, this animal had not reached 

 the same stage of development in the situation as had animal 

 83 9 . The general mode of performance and the end products 

 arc the same in both dogs although the exact course differs. 

 With animal 83 9 the disappearance of the conditioned re- 

 sponse and elimination of movement followed a gradual de- 

 crease in intensity. In the case of 219 $ the reaction was 

 more abrupt. 



Although the majority of the dogs classified in group A 

 formed a conditioned salivary response, in some cases it 

 was weak and continued for a short time only. Two of the 

 dogs, however, reached a state of complete inactivity before 

 forming the conditioned response. They developed a condi- 

 tioned orientation reaction to the pan, but this reaction was 

 suddenly eliminated, after which the animals attended only 

 to the rotation of the disk. One of these dogs, 336 9 , a three- 

 quarters dachshund and one-fourth Brussels griffon, is shown 

 in plate 100 (fig. 3). Within a short time they also refused 

 to eat unless deprived of food for 3 days or more. It seemed 

 that these animals were more lethargic in nature than the 

 dogs which formed the conditioned response. The non-es- 

 sential parts of the performance were eliminated earlier, 



