HEARING AND ALLIED SENSES IN FISHES. 
47 
blasting. Pollock did not respond, however, to the sound made by rubbing a wet 
linger on the glass window of an aquarium or to the noise made by striking a piece 
of glass under water with a stone, provided the means of producing the noise was 
not seen by the fishes. Bateson concluded that, while it may be regarded as clear 
that fishes perceive the sound of sudden shocks and concussions when these are 
severe, they do not seem to hear the sounds of bodies moving in the water but not 
seen by them. 
Without knowledge of Bateson’s observations, Kreidl (1895) carried out a series 
of experiments with the view of testing the powers of hearing in the gold-fish, Car- 
assius auratus. This species was chosen because of the ease with which it could be 
kept in the laboratory and, further, because it is one of those fishes that have long- 
been reputed to come at the sound of a bell. After an extended series of experi- 
ments, Kreidl (1895, p. 458) concluded that normal gold-fish never respond to sounds 
produced either in the air or in the water, though they do react to the shock of a 
sudden blow given to the cover of the aquarium. Individuals rendered abnormally 
sensitive by strychnine gave no response to the sound of a tuning-fork or a vibrating- 
rod even when these were in contact with the water, though the fishes responded at 
once to such slight shocks as tapping the aquarium, etc., or even clapping the 
hands vigorously in the air. 
To test whether these responses were dependent upon the auditory nerves, 
Kreidl removed these nerves and the attached ear-sacs from a number of individ- 
uals, and, after poisoning them with strychnine, subjected them to stimulation by 
sound. In all cases they were found to respond precisely as the poisoned animals 
with ears did. Kreidl, therefore, concluded that gold-fishes do not hear by the 
so-called ear, but that they react to sound-waves by means of an especially developed 
cutaneous sense, or, to put it in other words, the gold-fish feels sound but does not 
hear it (Kreidl, 1896, p. 581). 
After having reached this conclusion, Kreidl was led to take up a specific case 
of the response of fishes to the sound of a bell, and an opportunity for doing this 
was found at the Benedictine monastery in lvrems, Austria. Here the trout of a 
particular basin were said to come for food on the ringing of a bell. Kreidl (1896, 
p. 583), however, found that they would assemble at sight of a person and without 
the ringing 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 a 
small piece of bread Avas 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 no response was 
observed. From these facts Kreidl (1896, p. 584) concluded that the assembling of 
the fishes was brought about through sight and the cutaneous sense, and not through 
hearing, and that the conclusion reached with the gold-fish might be extended to 
other kinds of fishes. 
Kreidl’s conclusions were supported by the observations of Lee (1898), who 
studied the reactions of several species of fishes to such sounds as the human voice, 
the clapping of hands, and the striking of stones together in air and under water. 
In all of his experiments Lee (1898, p. 137) obtained no evidence whatever of the 
existence of a sense of hearing, as the term is usually employed, although he found 
that the fishes were exceedingly sensitive to gross shocks, such as the jarring of their 
