THE MEMORY OF FISHES.

Dominion, Volume 5, Issue 1497, 20 July 1912, Page 8

THE MEMORY OF FISHES.

In "Knowledge" for Juno, Professor Arthur Thomson describes Oxner's experiments with the eea perch, in order to test it; memory. His methods were us follow : He hung in sin aquarium a rt-d and a green cylinder by silk threads of similar colour, «iml put food into tho red one only. For the first hyo days the fish did' not approach (.he cylinders; on the third day, after fifteen minutes, it entered tho cj'lindcr and ate the food; on tho fourth day it did this after fivo minutes; on tho fifth day after half a minute; from tho sixth to the. ninth day it. rusher in at 011C4. Uu the eleventh day it entered a fresh red cylinder which had no food, and waited there for three minutes. An association had been established between the colour and the food. The fish rushed into tho empty red cylinder on each of tho succeeding six days, and when M. Oxiier dropped in soiiio food, a little was taken. On tho eighteenth, nineteenth, and twentieth days tho fish would not eat the food. Even in tho absence of appetite the iish seemed unable to resist rushing into the red cylinder. In other experiments the colours were altered,, but the sanio general results were obtained. There is no particular attraction in the red colour. What is cstabiisohd is first an asBiiciation, and'eventually something almost liko a. reflex. <