THE OLFACTORY REACTIONS OF THE NEWT 269 



were cut need not be reported in detail. The day after the opera- 

 tions both took meat from a probe and followed and snapped at 

 filter paper. If there were any general ill effects from the opera- 

 tions they could not be detected through any modification of 

 behavior. Tests with carmine indicated that the flow of water 

 through the nasal organs was normal. Both failed absolutely 

 to respond to meat juice squirted over the olfactory apertures, 

 although before the nerves were cut their reactions to it were 

 very pronounced. The effect of a moving object on the be- 

 havior of an animal deprived of the sense of smell was most 

 striking. In one instance it was only with great difficulty that 

 the seizing reaction could be induced, for the newt persisted in 

 its attempts to test the edibility of the meat by smell. It was 

 nosed constantly on being moved through the sand, but not 

 taken into the mouth. Finally, after continued agitation, it 

 was seized and swallowed. 



The results of the experiments last described indicate that 

 the olfactory receptors, and not the gustatory ones, are those 

 stimulated by substances in dilute solution such as meat juice. 

 When the stimulus is prevented from reaching the former, or 

 when their connections with the brain are severed, the results 

 are the same, viz., the seizing or snapping reaction does not 

 take place, provided, of course, it is not induced by a stimulus 

 of quite a different character. I conclude, therefore, that Die- 

 myctylus reacts to olfactory stimuli, and that the sense of 

 smell plays an important part in food recognition. 



The fact that a newt often seizes an inedible object such as 

 filter paper only when it is in motion demands some explana- 

 tion. In many cases this reaction probably occurs because the 

 motion of the object interferes with a satisfactory nosing of it, 

 and accordingly it is taken into the mouth where it may be 

 tested by taste. An animal following and attempting to scent 

 a moving piece of cotton or filter paper was of frequent occur- 

 rence, and very often the seizing reaction followed. In other 

 instances, however, there appeared to be no attempt on the 

 part of the animal to test the edibility of the object by the 

 sense of smell, for it was immediately pursued and secured. 

 An explanation of this behavior, I believe, is to be found in 

 the character of the natural food of the animal. An examina- 

 tion was made of the stomach contents of a dozen newts which 



