he connexions of the angular gyrus with
both visual centres, agraphia is not produced, for the visual word
centre and its connexion with the graphic centre are still intact (pure,
or sub-cortical word blindness).

_Motor Vocal Aphasia or Aphemia._--The centre for motor vocal speech is
situated in the posterior part of the third left frontal convolution and
extends on to the foot of the left ascending frontal convolution
(Broca's convolution). Complete destruction of this region produces loss
of speech, although it often happens that a few words, such as "yes" and
"no," and, it may be, emotional exclamations such as "Oh! dear!" and the
like are retained. The utterance of unintelligible sounds is still
possible, however, and there is neither defective voice production
(_aphonia_) nor paralysis of the mechanism of articulation. The
individual can recall the auditory and visual images of the words which
he wishes to use, but his memory for the complicated, co-ordinated
movements which he acquired in the process of learning to speak, and
which are necessary for vocal expression, has been blotted out. In the
great majority of cases of motor vocal aphasia there is associated
agraphia, a circumstance which is perhaps to be accounted for by the
proximity of the graphic centre. When the lesion is situated below the
cortex of Broca's convolution but destroys the fibres which pass from it
towards the internal capsule, agraphia is not produced (sub-cortical or
pure motor vocal aphasia). Destruction of the auditory speech centre is,
as we have seen, commonly accompanied by more or less interference with
vocal speech, a consequence of _amnesia verbalis_.

_Agraphia._--Discussion still rages as to the presence of a special
writing centre. Those who favour the separate existence of a graphic
centre locate it in the second left frontal convolution. It may be that
the want of unanimity as to the graphic centre is to be explained by an
anatomical relationship so close between the graphic centre and that for
the fine movement of the hand that a lesion in this situation which
produces agraphia must at the same time cause a paralysis of the hand.
Destruction of the visual speech centre by obliterating the visual
memories of words (_amnesia verbalis_) produces agraphia. Further,
several instances are on record in which agraphia has followed
destruction of the commissure between the visual speech centre and the
graphic centre. As already menti