ADAPTATIONS 391 



port or shock of the explosions made in blasting operations of 

 rocks in the neighbourhood were followed by sudden move- 

 ments in conger, flat-fishes, and pouting ; while other fishes 

 seemed to take no notice of the reports. When the side of the 

 tank was struck by a heavy stick similar movements were pro- 

 duced. Pollack, however, made no response to the vibrations 

 produced by striking a piece of glass with a stone under water 

 provided the objects used were not visible to the fish. Bateson 

 concluded that fishes perceive the sound of sudden shocks and 

 concussions when sufficiently severe, but do not hear the sounds 

 of bodies struck in the water but not perceived by them. 



In several cases it has been stated that gold-fishes or other 

 fresh-water fishes kept in ponds have been in the habit of 

 assembling for food at the sound of a bell, which would be 

 sufficient to prove not only that they possessed a sense of hearing 

 but that they could hear sounds produced in the air and trans- 

 mitted to the water. The Viennese physiologist Kreidl con- 

 cluded from his experiments on the gold-fish that it made no 

 response to sounds produced either in the air or in the water 

 but only reacted, as Bateson found, to the shock of a blow given 

 to the sides or top of the aquarium. He further removed the 

 auditory nerves and the attached ear-sacs from several specimens 

 and found that they reacted to shocks in the same way as 

 uninjured fish. He concluded therefore that the fish does not 

 perceive vibrations by the ear at all, but only perceives strong 

 vibrations by the skin ; the ear, according to this result, would 

 only be concerned with the sense of equilibrium and direction 

 which is one of its functions in ourselves. Kreidl investigated 

 a special case of the assembling of fishes at the sound of a 

 bell, namely the trout of a particular basin at the Benedictine 

 Monastery of Krems in Austria. He found that the trout 

 assembled equally at the sight of a person when no bell was 

 rung, and if the bell was rung by a person whom they could 

 not see the trout took no notice. If, however, a pebble or a 

 piece of bread were thrown into the water the fish swam to 

 the spot where the water was disturbed. Kreidl, therefore, 

 maintained that the fishes were only affected by the sense of 

 sight and the sense-organs of the skin. The American physio- 

 logist Lee made similar experiments and obtained results 

 entirely in agreement with those of Kreidl. These results are, 



