us, which authorities hold to be concerned with the visual
memory of words. Study of diseased conditions of speech has shown that
the power to understand _written_ words may be lost or severely impaired
although the words may be perfectly distinct to the sight and although
the power to understand _heard_ words remains good. This condition is
asserted by many physicians to be referable to destruction of part of
the angular gyrus. Close beneath the cortex of the angular gyrus runs a
large tract of long fibres which pass from the visual cortex (see above)
to the auditory cortex (see below) in the superior temporal gyrus and to
the lower part of the frontal lobe. This lower part of the frontal lobe
is believed--and has long been believed--to be concerned intimately with
the production of the movements of speech. A difficulty besetting the
investigation of the function of the angular gyrus is the fact that
lesion of the cortex there is likely to implicate the underlying tract
of fibres in its damage. It cannot be considered to have been as yet
clearly ascertained whether the condition of want of recognition of seen
words--"word-blindness"--is due to cortical injury apart from
subcortical, to the angular gyrus itself apart from the underlying
tract. Word-blindness seems, in the right-handed, to resemble the
aphasia believed to be connected with the lower part of the frontal
lobe, in that it ensues upon lesions of the left hemisphere, not of the
right. In left-handed persons, on the contrary, it seems to attach to
the right hemisphere.

_Auditory Region of the Cortex._--Besides the two great organs of
distance-receptors, namely, the nose and eye, whose cerebral apparatus
for sensation has just been mentioned, those of a third great
distance-receptor have to be considered. The agents of stimulation of
the two former are respectively chemical (olfactory) and radiant
(visual); the mode of stimulation of the third is mechanical, and the
sensations obtained by it are termed auditory. Their cerebral
localization is very imperfectly ascertained. Electric stimuli applied
to a part of the uppermost temporal gyrus excites movements of the ears
and eyes in the dog. Destruction of the same region when executed on
both hemispheres is argued by several observers to impair the sense of
hearing. To this region of cortex fibres have been traced from the lower
centres connected with the nerve-fibres coming from the cochlea of the
ear. From each