264 MANTON COPELAND 



two of these were swallowed. It was then fed with meat, after 

 which it nosed, but refused to snap at stationary filter paper. 

 The paper was next moved about in the water, when it was 

 actively followed and seized. 



From the experiments described above, it may be seen that, 

 in order to test satisfactorily the relation between chemical 

 stimulation and the seizing reaction, several factors must be 

 eliminated. The desired results were obtained in the following 

 way. Five animals, isolated in an aquarium, were carefully fed, 

 so as to prevent any danger of excessive hunger. Two wires 

 were fastened to a wooden bar so that their free ends reached 

 nearly to the bottom of the aquarium when the bar was laid 

 across the top. Two cheese cloth bags, 9 to 12 millimeters in 

 diameter, were next made, one of which was rilled with meat, 

 and the other with cheese cloth. The bags were then tied to 

 the ends of the wires, and the cross bar placed in position. By 

 this method, two bags of approximately the same size and ap- 

 pearance, were held about 33 centimeters apart, a few milli- 

 meters above the bottom of the aquarium. The reactions of the 

 newts to the bags were then watched for a half hour, the posi- 

 tions of the two being exchanged at the end of fifteen minutes. 

 The result of this experiment was as follows. The bag contain- 

 ing meat was approached and nosed about 29 times, and bitten 

 as many as 85 times. Since, frequently, three or four newts 

 were snapping at the bag at once, an accurate record was diffi- 

 cult to obtain. Reactions to the cheese cloth bag were quite 

 different. It was approached and nosed 1 7 times, but no attempt 

 was made to seize it. As the bag was being lowered into posi- 

 tion, it was snapped at by one of the animals, a response ini- 

 tiated by its movement. Three hours later, the experiment was 

 repeated with similar results. The baited bag was approached 

 and nosed 22 times, and bitten 94 times, whereas the other one 

 was nosed 9 times and not once seized. In neither experiment 

 was a case observed where an animal carefully nosed the baited 

 bag and then failed to snap at it. These tests show conclusively 

 that Diemyctylus is able to discriminate perfectly between two 

 bags, one containing meat and the other not, and that the food 

 sensing occurs after the bag is approached and before it is 

 snapped at, or taken into the mouth. 



The question next arose : Were the olfactory organs involved 



