THE OLFACTORY REACTIONS OF THE NEWT 267 



some meat juice, prepared by the method already mentioned, 

 was squirted over the nostrils of a newt in such a way that 

 the animal could not see the pipette. This was done ten times, 

 and each time the response was a snapping of the jaws. Ten 

 trials with water alone caused no reaction. At the conclusion 

 of these tests the external nares were covered with "Cur-a-cut." 

 Three quarters of an hour later the animal snapped at meat 

 offered it on a probe, followed it about the aquarium, and in 

 no way gave evidence that the presence of the celloidin cap 

 was disturbing. It was then tested ten times with meat juice 

 which called forth no response. The tests were repeated over 

 an hour later with similar results : the snapping reaction failed 

 to occur, although the animal followed and bit at filter paper in 

 a normal way. The "Cur-a-cut" was next removed, and after 

 15 minutes had elapsed, 10 tests were made with meat juice. 

 A positive response occurred four times. Twice the juice was 

 snapped at, once the sand, and once the sand was nosed. An 

 hour and a half later the reactions to the extract were the same 

 as in the first tests of the experiment, viz., 10 trials resulted in 

 10 snapping responses. Another individual gave a series of 

 reactions differing only in detail from the last. Four hours and 

 a half elapsed after the nostrils were covered before the animal 

 responded normally to filter paper and meat. Twenty tests 

 with meat juice then failed to induce the usual snapping reac- 

 tion. Five hours after the "Cur-a-cut" was removed, it was 

 tested with the juice, when it responded six or seven times in 

 10 trials. A third animal reacted to the meat extract somewhat 

 erratically on the first and second day after the nostrils were 

 covered. Upon examination it was found that the "Cur-a-cut" 

 had loosened so that one nostril was practically uncovered. 



From the results obtained in these two types of experi- 

 ments, one may fairly conclude that the usual snapping at beef 

 extract, or at a bag containing meat, is a reaction initiated by 

 a stimulation of the olfactory receptors, and that when an 

 object is nosed, it, in truth, is being tested by the sense of smell. 

 There is, however, another possible interpretation of this be- 

 havior, although one not at all probable. It is conceivable 

 that the stimulating materials may pass through the nasal 

 chambers and internal nares and affect the gustatory recep- 

 tors of the mouth, and that the failure of the animal to respond 



