THE OLFACTORY REACTIONS OF THE NEWT 263 



the ten trials. In the first experiment with cotton, plain and 

 soaked in meat juice, when there was practically no difference 

 in the appearance of the two pieces offered, similar results were 

 obtained. In both experiments, however, discrimination be- 

 tween the inedible and edible objects (if cotton soaked in beef 

 juice may be termed edible) was not perfect. The plain cotton 

 was taken twice, and the filter paper snapped at five times. Other 

 things, therefore, besides chemical stimulation may call forth the 

 seizing reaction. 



When the object, with which the test is being made, is fast- 

 ened to the end of a probe, and is offered in that way to the 

 animal, the movement of it becomes a possible factor in deter- 

 mining the response. Accordingly, the effect of motion of the 

 proffered object was next investigated. A ball of filter paper, 

 hooked to the end of a wire, was held firmly in position beneath 

 the water by the method already described. A newt was then 

 allowed to wander about the aquarium until it approached, 

 nosed and deserted the filter paper. The paper was then either 

 fastened to a probe and moved about near the animal, or it was 

 rolled over the sand on the bottom o_f the aquarium. Several 

 tests were made, involving three individuals. In three cases 

 the movement of the filter paper induced the seizing reaction. 

 One animal snapped it from the end of the probe four times in 

 succession, and the other two not only seized but swallowed it. 

 An inedible object in motion, therefore, may be taken into the 

 mouth or even swallowed, whereas the same thing stationary 

 is nosed and rejected. An explanation of this behavior is offered 

 on a succeeding page. 



Finally, as noted above, a fixed piece of filter paper is some- 

 times seized. Several factors may be influential in exciting this 

 reaction, but the most important one, I believe, is hunger. An 

 animal, which undoubtedly is very hungry, may cease tempo- 

 rarily to use its powers of discrimination, and seize and swallow 

 filter paper almost as readily as meat, even when the former 

 is not in motion. When, however, such an animal is fed, a 

 different reaction may be obtained. The filter paper ball is 

 then approached and nosed, but not seized. The following 

 tests serve to illustrate the effect of both hunger and a moving 

 object on the newt's feeding behavior. An animal took several 

 pieces of filter paper from a wire in a fixed position. One or 



