Although  the  various  instances  of  recurrent  tumours  which  have
been  recorded,  present  many  diversities  of  structure,  yet  they  may  be
said  generally  to  have  possessed  the  characters  of  incomplete  develop-
ment, to  have  exhibited  an  undue  preponderance  in  the  cell-elements
which  they  contained,  and  to  have  presented  the  embryonic  or  mdi-
mental,  rather  than  the  perfect  state  of  the  natural  tissues.  And  this
rule  of  persistent  or  arrested  embryonic  structure  in  the  recurrent
tumours  is  so  general,  that  in  practice  it  is  advisable  to  speak  with
hesitation  of  the  ultimate  result  of  any  case  in  which  a  tumour  is  found
to  be  composed  of  mdimental  tissues,  This  similarity  in  structure  to
embryonic  texture  becomes  more  strongly  marked  after  each  removal
and  recurrence.  A  tumour  which,  at  first,  might  be  not  unlike  the
normal  fibrous  or  glandular  texture  in  which  it  grew,  after  repeated
removal  and  recurrence  becomes  softer,  more  succulent,  and  in  its  later
growths  may  seem  to  the  naked  eye  little  more  than  like  masses  of  yel-
low or  ruddy  soft  gelatine  with  bloodvessels.  The  later  are  usually
much  more  rapid  in  their  progress  than  the  earlier  growths  :  they  are
generally  less  well  defined,  penetrating  farther  and  more  vaguely  among
the  interstices  of  adjacent  parts,  and  more  quickly  protruding  through
the  skin  or  scars  over  them,

And  in  these  characters  the  later-formed  tumours  assume  more  of
the  character  of  malignancy  than  the  earlier.  In  the  case  I  relate  on
p.  596,  the  last  tumour  was,  in  general  aspect,  hardly  to  be  distinguished
from  brain-like  tumour,  though  in  microscopic  characters  essentially  like
its  predecessors.  In  one  of  Professor  Gluge's  cases  the  transitions  to
completely  malignant  characters  appeared  yet  more  sure.  Mr.  Syme
also  expresses  a  similar  transition :  describing,  as  the  usual  course  of

'  Dr.  Wilks  also  has  recorded  a  case  {Path.  JVans.  x.  p.  244)  of  a  man  whose  leg
was  amputated  hy  Mr.  Cock  for  a  large  myeloid  tumour  of  the  head  of  the  fibula.  Two
years  afterwards  a  recurrence  took  place  in  the  stump.  Eemoval  was  again  performed,
and  a  few  days  afterwards  the  man  died  of  pleurisy.  At  the  post-mortem  examination,
secondary  myeloid  tumours,  of  considerable  size,  were  hanging  pendulous  from  the
exterior  of  the  lungs,  but  not  infiltrating  their  substance.  But  the  more  frequent  result
of  amput  itions  for  recurrent  tumours  of  the  limbs  has  been  an  apparently  final  remedy.
