THE AUDITORY REACTIONS OF THE DOG 145 



established, standard stimulation, and some unusual stimulation. 

 Thus, the dog is able to differentiate distinctly between 104 and 

 100 beats (standard) if the new rate is tested 10, 15, 45, or 60 

 minutes later. The differentiation is less certain after 18 hours 

 of intermission and vanishes completely after a lapse of 4'5 hours. 



In responding to various intermittent stimuli of unaccustomed 

 frequency a remarkable regularity and uniformity stamps the 

 results. Applied immediately after stimulation with the standard 

 rate of oscillation it produces a distinct depressing effect on the 

 salivary secretion in the first trial. During the subsequent few 

 trials the conditioned salivary reflex increases considerably, 

 then again diminishes to complete disappearance in further 

 tests. -These facts are very important because they offer a clue 

 to the analysis of the phenomenon of inhibition. 



This review purports to bring once more before the attention 

 of American investigators the enormous value of this purely 

 objective analytical method in animal psychology and to stimulate 

 an active interest in the subject which should soon lead to a 

 systematic investigation of the reactions of various animals by 

 this method. 



