130 JOURNAL OF COMPARATIVE NEUROLOGY. 
bined stimulus of tactile and gustatory end-organs. At first 
the fish may react similarly to a pure tactile stimulus and the 
tactile plus the gustatory. After a brief training, however, he 
acquires the ability to discriminate between the former, which is 
never followed by satisfaction, and the latter, which is followed 
by the pleasure of feeding. Clearly the fish learns by experi- 
ence. We find also some differences between the different spe- 
cies of fishes in this respect, depending on the relative impor- 
tance of the tactile and gustatory elements of the sensation com- 
plex in the normal reflex life of the fish. 
It would be interesting to inquire the part played by 
memory in these reactions. In the case of Ameiurus, where 
the tactile and gustatory elements of the reflex of seizing food 
can be experimentally isolated by training, it would doubtless 
g, 
be possible to measure quantitatively the duration of the per- 
sistence of this acquired discrimination. I have made no accu- 
rate observations on this point, but can say in general that the 
memory of these fishes seems to be fairly good. (By the term 
memory I do not mean to prejudice the question of the part 
played by consciousness here. The original reaction may be 
largely or wholly an unconscious or automatic response and the 
“memory”? may be an organic memory more closely allied to 
habit). At the beginning of the tests’ with cotton the cat fishes 
generally seized the cotton just as they did the meat. At the 
close of the first day’s experiments they had learned to ignore 
the cotton asa rule, and half an hour after the close of this se- 
ries of tests they still would pay small attention to the cotton ; 
but by the day following, if tested first with meat, they would 
take the cotton for-a few times or would react to it slightly 
during the first few tests, but would learn to let it alone sooner 
than on the first day. But toward the close of the experiments 
after several weeks of practice I rarely got any reaction at all 
with the cotton under any circumstances, even if the fishes had 
not been tested for several days. With the gadoids the num- 
ber of experiments was much smaller and they were continued 
for a shorter time, but I never got so good evidence of memory 
of the discrimination. On successive days the tests were much 
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