10.  The  cortical  centres  of  hearing,  smell,  a3id  taste,  are  probably
associated  (wholly  or  in  part)  with  the  corresponding  organ  of  the  oppo-
site side.  Hence,  we  may  clinically  refer  an  abolition  of  the  function  of
hearing  (in  case  it  be  due  to  a  cortical  lesion)  to  the  hemisphere  opposed
to  the  deaf  ear.  ''  Word-deafness"  ma}'  ensue,  liowever,  when  the  centres
of  hearing  of  only  one  cerebral  hemisphere  are  involved.  In  right-handed
subjects,  the  left  superior  temporal  convolution  appears  to  govern  this
function;  while,  in  left-handed  subjects,  the  right  superior  temporal  con-
volution assumes  it.  This  is  probably  due  to  the  fact  that  the  hemi-
sphere which  is  the  most  exercised,  becomes  more  rapidly  developed.
11.  When  the  third  frontal  convolution  is  alone  diseased,  the  patient
w^ill  l)e  able  to  understand  spoken  or  written  questions  perfectly,  but
will  not  be  able  to  properl}'  regulate  the  movements  of  the  speech  ai)pa-
ratus  that  are  requisite  to  a  reply.
12.  When  the  superior  temporal  convolution  is  alone  diseased,  the
patient  cannot  recognize  or  properly  interpret  spoken  language.  He
ma}',  however,  be  able  to  repeat  single  words  when  propounded,  but  not
sentences.  Exclamations  of  various  kinds  ma}'  be  uttered  by  these  sub-
jects when  irritated  or  distressed  ;  but  they  are  more  or  less  involuntary,
and  often  irrelevant.  The  efforts  of  these  patients  to  talk  or  read  aloud
are  peculiarly  unintelligible.
