OLFACTORY REACTIONS OF SPHEROIDES 367 
reactions to the packets again resulted, characterized by normal 
discrimination between the two. In a fifteen minute test the 
baited packet was bitten 28 times, and the other one twice. 
These experiments show that reactions to concealed food cease 
when the olfactory apparatus is rendered inoperative, and are 
resumed only when the organs again become functional. 
A week later the foregoing experiments were repeated, and an 
attempt made to hasten the recovery of the olfactory organs by 
shortening the time during which they were to be tied. ‘Two of 
the four puffers previously tested were isolated in an aquarium 
and allowed to become hungry. They then reacted in an essen- 
tially normal way to the two packets, biting the one with meat 34 
times, and the other 10 times in one hour. For eleven minutes 
after the packets had been suspended in the aquarium, no appar- 
ent attention was given them, although both fish were passing 
and repassing them constantly. Suddenly one of the puffers ap- 
proached the packet containing meat and bit it. It was a reaction 
which any unprejudiced observer would have called olfactory. 
After this test, the nasal organs were tied, and about two hours 
later the fish were again tested for an hour. The thread which 
surrounded one of the organs dropped off shortly before the test 
was made. Neither of the packets was touched, although before 
and after the test both fish ate pieces of meat from the end of a 
wire in their habitual way. The threads were immediately re- 
moved, and, on the following day, they were given two one-hour 
_ tests with the packets. No reactions to either resulted. Forty 
hours after untying the threads they were again tested. One of 
the fish bit 8 times at the packet with meat and 5 times at the 
one made of cheese cloth, whereas the other fish ignored both. 
Each ate actively from the end of a wire at the conclusion of the 
test. 
Subsequent examination of the condition of the nasal organs 
of these two puffers showed that such behavior might have been 
expected, if concealed food is scented by means of these organs. 
Both organs of the fish which failed to react were so badly crushed 
by the second tying that they could not have been functional after- 
ward. The second puffer, however, showed one organ substan- 
THE JOURNAL OF EXPERIMENTAL ZOOLOGY, VOL. 12, NO. 3 
