cochlear nerve a path has been traced which passes to the
_insulae_ and the above-mentioned _temporal_ region of cortex of both
the cerebral hemispheres. The insula is a deeper-seated area of cortex
adjoining the uppermost temporal convolution. To it Flechsig's
chronological studies also impute a connexion with the nerves of the
ear. Early myelinization of fibres, presence of ascending and descending
"projection" tracts to and from lower centres outside the cortex,
calibre of fibres, microscopic characters of its cortical cells, all
those kinds of indirect items of evidence that obtain for the visual
cortex likewise mark out this insular-temporal area as connected fairly
directly with a special sense-organ, as in fact a sensory field of the
cortex; and the suspicion is that it is auditory. Clinical observation
supports the view in a striking way, but one requiring, in the opinion
of some, further confirmation. It is widely believed that destruction of
the upper and middle part of the uppermost temporal convolution produces
"word-deafness," that is, an inability to recognize familiar words when
heard, although the words are recognized when seen.

More precise information regarding this auditory region of the cortex
has recently been obtained by the experiments of Kalischer. These show
that after removal of this region from both sides of the brain in the
dog the animal shows great defect in answering to the call of its
master. Whereas prior to the operation the animal will prick its ears
and attend at once to the lightest call, it requires after the removal
of the auditory regions great loudness and insistence of calling to make
it attend and react as it did. This is the more striking in view of
other experimental results obtained. Kalischer trained a number of his
dogs not to take meat offered them except at the sound of a particular
note given by an organ pipe or a harmonium. The dogs rapidly learned not
to take the food on the sounding of notes of other pitch than the one
taught them as the permissive signal. This reaction on the part of the
animal was not impaired by the removal of the so-called auditory regions
of the cortex. Kalischer suggests that this reaction taught by training
is not destroyed by the operation which so greatly impairs the common
reaction to the master's call, because the former is a simpler process
more allied to reflex action. In it the attention of the dog is already
fastened upon the object,