438 JOHN B. WATSON 



platform arranged inside the cage. The apparatus producing 

 the noises was out of sight. About 80 trials were required for 

 monkey 4 to complete the discrimination. Monkey 6 formed 

 the habit in no trials, whereas monkey 5 failed to acquire the 

 habit in the time allotted for the experiment. 



Shepherd's experiments upon pitch discrimination were quite 

 crude. The German mouth harp was used for producing the 

 tones. At the sound of the higher tone, A3 (?), the monkey was 

 expected to respond by climbing to the platform used in the 

 intensity-discrimination test. When Aj (?), two octaves lower, 

 was sounded, the monkey was expected to refrain from climbing. 

 It was not fed when the lower tone was given. Monkey 4 learned 

 to respond correctly in three days (60 trials) ; monkey 6, in four 

 da^'s (80 trials), while monkey 5 did not learn to make the 

 response within the time limits of the experiment. 



OLFACTION 



Fish. Parker,^" experimenting on the feeding movements of 

 the common fresh water catfish, finds that the animals remain 

 in a state of considerable excitement after the last morsel of 

 food has been eaten. During the period of excitement the fish 

 swim about in the lower part of the aquarium in various direc- 

 tions, frequently sweeping the bottom with their barblets. In 

 actual feeding they seldom seize food until their barblets have 

 come in contact with it. Since they show excitement at a dis- 

 tance, it would seem that they scent their food. That the olfac- 

 tory apparatus really functions follows from the operative 

 experiments of Parker. In one set of five animals he removed 

 the barblets, thus partially eliminating the sense of taste. In 

 another set of five he sectioned the olfactory tract and threw 

 the peripheral mechanism out of function. When tested for one 

 hour in a tank which contained chopped worms placed in a 

 cheesecloth bag, the fish with barblets removed seized the food 

 34 times. The anosmic animals, on the contrary, did not seize 

 it at all. A cheesecloth bag without the worms was then sub- 

 stituted : no fish of either of the two groups seized it. Repeated 

 tests of this kind furnished Parker evidence for affirming that 

 the catfish, " though a water inhabiting animal, possesses an 

 olfactory organ that is as much an organ of smell as is the olfac- 

 tory organ of the air inhabiting vertebrates." 



