THE OLFACTORY REACTIONS OF THE NEWT 261 



chewed for a while, and discarded. Instead of testing the ani- 

 mal again with meat, an extract was prepared by grinding raw 

 beef in water and filtering the fluid. A piece of cotton was 

 then soaked in this juice, and offered the animal as before. 

 By this procedure the introduction of new visual or tactile 

 factors was practically avoided, for the color of the cotton was 

 changed only slightly by the juice. It was seized, chewed upon 

 and swallowed. Plain cotton was then refused. When the 

 cotton was moved the newt followed it about, resting the tip 

 of the snout upon it. Cotton soaked in juice was then nosed 

 in a similar way until it dropped off the probe. When rolled 

 over the sand, the cotton ball was pursued and again nosed. 

 Finally it was snapped into the mouth and swallowed. Plain 

 cotton, presented to the animal in exactly the same way, was 

 nosed but not taken. Lastly, another piece soaked in juice 

 was offered. As in the two preceding tests, the animal nosed 

 it several times but did not seize it. When moved with the 

 probe, it was taken and swallowed. A piece of meat was then 

 refused. 



A study of the behavior exhibited in this experiment reveals 

 a number of reactions which were found to be characteristic 

 of other individuals under appropriate stimulation. First, there 

 is an approaching or following reaction. The hungry animal 

 approaches a motionless object, or follows one moved in front 

 of it. Secondly, there occurs a nosing reaction, which consists 

 of placing the anterior end of the snout, where the external 

 nares are situated, on the object under investigation, where it 

 may be held for several seconds. This reaction is strongly sug- 

 gestive of "smelling," and is one of the most striking occur- 

 rences in the feeding behavior of the newt. Thirdly, the object 

 may be seized or snapped at, and lastly, if taken into the mouth, 

 it may be swallowed. The problem lay in determining whether 

 any one of these reactions is initiated by a stimulation of the 

 olfactory receptors. 



The approaching reaction. The approaching reaction was 

 first studied. The importance of sight in this response was 

 easily demonstrated. If a small piece of meat on the end of 

 a w 7 ire was moved about in the water four or five centimeters 

 in front of an animal, it was eagerly pursued. When one ap- 

 proached the meat, others usually followed, until all the occu- 



