FEEDING REACTIONS OF AMBYSTOMA 59 
as it was presented, but did not seize the other packet. Obviously 
the capacity to discriminate between the edible and inedible 
objects in these experiments involved the olfactory sense. 
It may be noted in passing that these animals do not always 
discriminate thus clearly between edible and inedible objects. 
Some of them did at times approach and seize inedible objects 
which emitted no odor. After repeated attempts following the 
presentation of food a few animals were induced to seize pledg- 
ets of cotton. In at least one instance such a pledget of cotton 
was also swallowed. 
In order to determine more accurately the relative impor- 
tance of the sense of sight and the olfactory sense in the feed- 
ing reactions several hungry animals were rendered sightless by 
enucleation of their eyes, while several others were subject- 
ed to an operation under ether anesthesia in which the anterior 
portion of the cranial cavity was laid open and the olfactory 
nerves were severed. The former operation caused the ani- 
mals little apparent discomfort. The latter was more severe; 
however, all but one of the animals recovered promptly. Both 
the de-eyed animals and those which had recovered after resec- 
tion of the olfactory nerves took food on the day following the 
operations and were not less active than the unoperated ani- 
mals. 
When small pieces of crayfish’s meat were held before the 
de-eyed animals they promptly seized and ate them. They even 
followed pieces of crayfish’s meat moved before them. When in- 
edible objects which emitted no odor were held before them they 
did not react unless the objects were in actual contact with them. 
In such instances they would sometimes attempt to seize them 
just as normal animals sometimes attempt to seize inedible ob- 
jects which come close to or in contact with them. The de-eyed 
animals reacted essentially in the same manner on successive 
days as long as they were kept under observation. Obviously 
their ability to discriminate between edible and inedible objects 
involved the olfactory sense. 
When pieces of crayfish’s meat or other food were held be- 
fore the animals whose olfactory nerves were severed, they were 
promptly seized and eaten. When inedible objects were pre- 
sented in the same manner they were seized just as promptly. 
