No. 435.] SENSE OF HEARING IN FISHES. 



rium. To test whether such responses were dependent upon the 

 auditory nerves, Kreidl removed these nerves and the attached 

 ear-sacs from a number of goldfishes and subjected them to stim- 

 ulation by sound. In all eases they were found to respond pre- 

 cisely as the animals with ears did. Kreidl, therefore, concluded 

 that goldfishes do not hear by the so-called ear, but that they 

 react to sound waves by means of an especially developed skin 

 sense, or, to put the matter in other words, the goldfish feels 

 sound but does not hear it (Kreidl. 1896. p. 5S1).' This condi- 



them, as anyone can prove by placing his hand under water near 

 a loudly sounding body. 



After Kreidl had reached his conclusion concerning goldfishes, 

 he was led to take up a specific case of the response of fishes 

 to the sound of a bell and an opportunity of doing this was 

 found at the Benedictine monastery in Krems, Austria. Here 

 the trout of a particular basin were'said to come for food at the 

 ringing of a bell. Kreidl (1896, p. 583), however, found that 



of the bell. If they were not then fed, they soon dispersed and 

 no amount of bell-ringing would induce them to return. If. 

 however, a pebble or small piece of bread was thrown into the 

 water, they immediately swam vigorously toward the spot where 

 the disturbance had occurred. Moreover, if a person approached 

 the basin without being seen and rang the bell vigorously, the 

 fishes did not assemble. From these facts Kreidl (1896, p. 584) 

 concluded that the assembling of the fishes was brought about 

 through sight and the skin sense and not through hearing, and 

 that the conclusion reached with the goldfish might be extended 

 to other kinds of fishes. 



While the problem of the auditory function of the ears of 

 fishes was thus being investigated, a wholly different view as 

 to the functions of these organs had been gradually opened up. 

 Through the researches of Loeb (1888), Kreidl (1892), Bethe 

 (1894), and Lee (1898) it became clear that whether the ears of 

 fishes were auditory organs or not, they were, beyond doubt, 

 organs for the control of the equilibrium of these animals, and in 



