In  some  cases  the  patient  has  been  able  to  read  aloud  correctly,  but  did  not
understand  what  he  read.  The  effect  on  writing  is  similar  to  the  effect  on
speech,  but  greater,  owing  to  the  double  symbolism  and  the  extension  of
error  thus  produced.
We  have  seen  that  in  partial  word  deafness,  partial  from  the  beginning  or
partial  by  recovery,  a  condition  exists  in  which  there  is  great  difficulty  in
the  voluntary  revival  of  words,  especially  of  the  more  special  words,  such  as
nouns.  This  is  the  "  verbal  amnesia,"  or  "  amnesic  aphasia,  "f  As  already
stated,  it  sometimes  constitutes  the  sole  defect  from  the  beginning,  and  is
then  commonly  regarded  as  a  distinct  variety  of  aphasia,  and  has  been
ascribed  to  interruption  of  the  conducting  path  between  the  auditory  and
motor  centres  (see  above,  p.  546).  Whether  the  condition  is  actually  thus
produced,  and  whether  a  simple  interruption  of  this  path  can  produce  this
effect,  remains  to  be  proved.  The  condition  is  often  conjoined  with  slight
word  deafness,  and  then  is  probably  due  to  a  partial  lesion  of  the  auditory
word  centre.  It  may  not  only  be  a  residual  condition  left  by  partial  recovery
from  a  considerable  degree  of  word  deafness,  but,  as  we  have  seen  (p.  548),
it  may  be  left  by  recovery  from  complete  and  pure  motor  aphasia.  The
fact  that  a  typical  "amnesic  aphasia"  may  be  merely  a  residual  condition
left  by  a  pure  motor  aphasia  is  very  important.  It  is  proved  by  several
recorded  cases  in  which  an  autopsy  was  obtained. J  Another  important
fact  is  that  the  loss  follows  a  regular  law  from  the  general  to  the  special.
