The Dawn of Mind 213 



The Mind of a Minnow 



To find solid ground on which to base an appreciation of the 

 behaviour of fishes, it is necessary to experiment, and we may 

 refer to Miss Gertrude White's interesting work on American 

 minnows and sticklebacks. After the fishes had become quite at 

 home in their artificial surroundings, their lessons began. Cloth 

 packets, one of which contained meat and the other cotton, were 

 suspended at opposite ends of the aquarium. The mud-minnows 

 did not show that they perceived either packet, though they swam 

 close by them; the sticklebacks were intrigued at once. Those 

 that went towards the packet containing meat darted furiously 

 upon it and pulled at it with great excitement. Those that went 

 towards the cotton packet turned sharply away when they were 

 within about two inches off. They then perceived what those at 

 the other end were after and joined them a common habit 

 amongst fishes. Although the minnows were not interested in 

 the tiny "bags of mystery," they were even more alert than the 

 sticklebacks in perceiving moving objects in or on the water, and 

 there is no doubt that both these shallow-water species discover 

 their food largely by sense of sight. 



The next set of lessons had to do with colour-associations. 

 The fishes were fed on minced snail, chopped earthworm, frag- 

 ments of liver, and the like, and the food was given to them from 

 the end of forceps held above the surface of the water, so that 

 the fishes could not be influenced by smell. They had to leap out 

 of the water to take the food from the forceps. Discs of coloured 

 cardboard were slipped over the end of the forceps, so that what 

 the fishes saw was a morsel of food in the centre of a coloured 

 disc. After a week or so of preliminary training, they were so 

 well accustomed to the coloured discs that the presentation of one 

 served as a signal for the fishes to dart to the surface and spring 

 out of the water. When baits of paper were substituted for the 

 food, the fishes continued to jump at the discs. Wken, however, 

 a blue disc was persistently used for the paper bait and a red disc 



