THE SENSE OF HEARING
Repeatedly in the foregoing chapters mention has been
made of the dancer’s irresponsiveness to sounds,
but it has not been definitely stated whether this
peculiarity of behavior is due to deafness or to the
inhibition of reaction. This chapter is concerned
with the evidence which bears upon the problem of
the existence of a sense of hearing. Again I may
be permitted to call attention to the observations
of other investigators before presenting the results
of my own experiments and stating the conclusions
which I have reached through the consideration of all
available facts.
By the results of various simple tests which he made,
Rawitz (25 p. 238) was convinced that the adult dancer
is totally deaf. He did not experiment with the
young, but he says he thinks they may be able to hear,
since the necessary structural conditions are present.
This guess which Rawitz made on the basis of very
indefinite and uncertain knowledge of the histology
of the ear of the young dancer is of special interest
in the light of facts revealed by my own experiments.
Unfortunately the study of hearing made by Rawitz
is casual rather than thorough, and although it may
turn out that all of his statements are justified
by his observations, the reader is not likely to get
much satisfaction from his discussion of the subject.
Inasmuch as he could discover no structural basis
for deafness, Panse (23 p. 140) expressed himself
as unwilling to believe that the mice are deaf, and
this despite the fact that he observed no responses
to the sounds made by a series of tuning forks ranging
from C5 to C8. He believes rather that they are
strangely irresponsive to sounds and that their sensitiveness
is dulled, possibly, by the presence of plugs of wax
in the ears. Since another investigator, Kishi,
has observed the presence of similar plugs of wax
in the ears of common mice which could hear, there
is but slight probability that Panse is right in considering
the plugs of wax as the cause of the dancer’s
irresponsiveness to sounds.
Far more thoroughgoing tests than those of Rawitz
or Panse were made by Cyon (9 p. 218), who holds the
unique position of being the only person on record
who has observed the adult dancer give definite reactions
to sounds. To a Koenig Galton whistle so adjusted
that it gave a tone of about 7000 complete vibrations
per second, which is said to be about the pitch of
the voice of the dancer, some of the animals tested
by Cyon responded unmistakably, others not at all.
In one group of four mice, two not only reacted markedly
to the sound of the whistle but apparently listened
intently, for as soon as the whistle was blown they
ran to the side of the cage and pressed their noses
against the walls as if attempting to approach the
source of the stimulus. The remaining two mice
gave not the slightest indication that the sound acted
