ed, the musical sounds being
received in the auditory centre very near the area for words heard
(_A_) while the centre for musical expression is also in the Rolandic
region. Furthermore, as may be surmised, the reading of musical
notation requires the visual centre, just as does the reading of
words. In addition to this, we find the curious fact that the location
of the whole speech zone is in one hemisphere only. Its location on
the left or the right, in particular cases, is also an indication as
to whether the person is right-or left-handed; this means that the
process which makes the individual either right or left-handed is
probably located in the speech zone, or near it. A large majority of
persons have the speech zone in the left hemisphere, and are
right-handed; it will be seen that the figure (5) shows the left
hemisphere of the brain, and with it the right hand holding the pen.

_Defects of Speech--Aphasia._--The sorts of injury which may befall a
large zone of the brain are so many that well-nigh endless forms of
speech defect occur. All impairment of speech is called Aphasia, and
it is called Motor Aphasia when the apparatus is damaged on the side
of movement.

If the fibres coming out from the speech zone be impaired, so that the
impulses can not go to the muscles of articulation and breathing, we
have Subcortical Motor Aphasia. Its peculiarity is that the person
knows perfectly what he wants to say, but yet can not speak the words.
He is able to read silently, can understand the speech of others, and
can remember music; but, with his inability to speak, he is generally
also unable to write or to perform on a musical instrument (yet this
last is not always the case). Then we find new variations if his
"lesion"--as all kinds of local nervous defects are called--is in the
brain centre in the Rolandic region, where arise the memories of the
movements required. In this latter case the aphasic patient can
readily imitate speech so long as he hears it, can imitate writing so
long as it lies before him, but can not do any independent speaking or
writing for himself. With this there goes another fact which
characterizes this form of aphasia, and which is called Cortical, as
opposed to the Subcortical Motor Aphasia described above, that the
person may not be able even to think of the words which are
appropriate to express his meaning. This is the case when those
persons who depend upon the memories of the movements