THE  brain,  being  the  material  instrument  of  the  intelli-
gence, the  physical  medm  through  which  the  mind
manifests  its  varied  powers,  it  is  in  conformity  with  the
rules  of  logic,  and,  in  obedience  to  the  laws  of  inductive
reasoning,  to  infer,  that  no  changes  in  its  structure  or  in-
vesting membranes  can  take  place,  no  alteration  in  the
quality  of  the  vital  fluid,  or  anatomical  character  or
calibre  of  the  numerous  bloodvessels  that  circulate  and
ramify  through  its  substance  can  exist,  without,  to  some
extent,  interfering  with,  or  modifying  its  psychical  func-
tions. Cases,  however,  are  on  record,  in  which  serious
injury  has  been  done  to  the  brain  during  life  without
damaging  the  intelligence,  and  considerable  encephalic
disorganization  (as  the  result  of  disease)  has  taken  place,
no  aberration,  exaltation,  depression,  or  impairment  of
the  mind,  having  been  observed,  previously  to  death.  If
such  cases  have  occurred,  they  must  be  considered  either
of  a  rare  and  exceptional  character,  or,  as  pathological
curiosities,  unless,  in  every  instance,  the  alteration  of
structure  is  strictly  confined  to  one  hemisphere,  or  re-
stricted to  the  fibrous,  or  conducting  part  of  the  nervous
structure,  the  vesicular  matter,  and  its  minute  vessels  re-
maining intact,  and  entirely  free  from  all  morbid  change,
or  abnormal  modification.  Is  it  possible  to  conceive  any
great  extent  of  disorganization,  even  in  the  medullary
portion  of  the  cerebral  mass,  to  exist,  witliout  impli-


EFFECT  OF  DISEASE  OF  THE  BRAIN  ON  THE  MINI).
eating,  to  some  degree,  the  grey  matter  of  the  brain,  and,
as  a  consequence,  deranging  the  phenomena  of  thought  ?

It  is  not  my  intention  to  discuss  in  this  work  the
complex  questions  (physiological  and  metaphysical)  in-
volved in  an  analysis  of  the  psycho-somatic  relation  or
union  between  mind,  and  matter,  life,  and  organization.
