FEEDING REACTIONS OF AMBYSTOMA 57 
the animals somewhat reluctantly seized pledgets of plain cot- 
ton which were brought in contact with their mouths, but made 
no attempt to swallow them. The results of these experiments 
show clearly that in the absence of sight these animals were 
guided in their feeding reactions by the olfactory sense. 
An attempt was now made to eliminate the sense of smell by 
filling the nares loosely with cotton. A more drastic opera- 
tion on these small animals, e. g., severing the olfactory nerves, 
did not seem advisable. The nares of five animals were filled 
loosely with cotton. One hour later they all appeared quite 
normal and were leisurely moving about the aquarium. Cray- 
fish’s meat dropped on the floor of the aquarium apparently 
was not noticed by them, neither would they seize bits of eray- 
fish’s meat held before them. On the following day they again 
refused to accept bits of erayfish’s meat held before them. The 
cotton was now extracted from the nares of three of the ani- 
mals. The nasal epithelium was inflamed and somewhat 
cedematous. Crayfish’s meat held before them was again re- 
fused. On the following day one of the animals from the nares 
of which the cotton had been extracted seized and ate a bit of 
the erayfish’s meat, but the others still manifested no interest 
in food held before them. These animals manifested less in- 
terest in food during the entire series of experiments than nor- 
mal hungry animals would in inedible objects presented to 
them in the same manner. We are of the opinion that the 
sense of smell was effectively eliminated by filling the nares 
loosely with cotton, but that the animals were somewhat dis- 
comfited by the inflammation of the nasal epithelium which 
followed and that the olfactory sense was not restored follow- 
ing the extraction of the cotton until the inflammation sub- 
sided. Obviously their failure to accept food held before them 
was in part determined by their discomfort. More crucial 
experiments designed to eliminate the sense of smell in young 
adults will be discussed presently. 
Young adults. As pointed out above, the larvae of Ambys- 
toma tigrinum cease feeding as they approach the final phase 
of their metamorphosis, and do not resume feeding until their 
metamorphosis is completed; consequently the majority of the 
young adults taken as well as those which emerged from the 
