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XXXV.  Description  of  a  Microscopic  Entozoon  infesting  the  Muscles  of  the  Human  Body. 
By  Richard  Owen,  Esq.,  F.R.S.  Z.S.,  Assistant  Conservator  of  the  Museum  of  the 
Royal  College  of  Surgeons  in  London. 
Communicated  February  24,  1835. 
Upwards  of  fifteen  distinct  kinds  of  Entozoa,  or  internal  parasites,  are  already 
known  to  infest  the  human  body ;  but  none  have  been  found  of  so  minute  a  size,  or 
existing  in  such  astonishing  numbers,  as  the  species  about  to  be  described. 
The  body  of  an  Italian,  set.  50,  who  had  died  in  St.  Bartholomew's  Hospital,  was 
brought  into  the  dissecting-room,  and  it  was  observed  by  Mr.  Paget,  an  intelligent  stu- 
dent, that  the  muscles  presented  an  uncommon  appearance,  being  beset  with  minute 
whitish  specks.  This  condition  of  the  muscles  had  been  more  than  once  noticed  by 
my  friend  Mr.  Wormald,  the  Demonstrator  of  Anatomy,  in  subjects  dissected  at  St.  Bar- 
tholomew's during  previous  anatomical  seasons.  His  attention  had  been  especially 
called  to  it  on  account  of  a  gritty  sensation  sometimes  perceived  in  dissection,  from 
which  circumstance,  and  the  rapid  blunting  of  the  scalpels  employed,  he  was  induced 
to  consider  the  appearance  as  being  caused  by  a  deposition  of  specks  of  earthy  matter. 
Mr.  Wormald  having  acquainted  me  with  this  fact,  I  expressed  a  desire  to  be  furnished 
with  portions  of  muscle  so  affected,  and  through  my  friend's  prompt  attention,  I  soon 
received  ample  materials  for  microscopical  examination  from  the  subject  above  men- 
tioned i. 
With  a  magnifying  power  of  an  inch  focus  the  white  specks  in  the  muscle  are 
seen  to  be  cysts  of  an  elliptical  figure,  with  the  extremities  in  general  attenuated, 
elongated,  and  more  opake  than  the  body  (or  intermediate  part)  of  the  cyst,  which 
is,  in  general,  sufficiently  transparent  to  show  that  it  contains  a  minute  coiled-up  worm. 
On  separating  the  muscular  fasciculi  the  cysts  are  found  to  adhere  to  the  surrounding 
cellular  substance  by  the  whole  of  their  external  surface,  somewhat  laxly  at  the  middle 
dilated  part,  but  more  strongly  by  means  of  their  elongated  extremities,  so  as  to  ren- 
der it  generally  a  matter  of  some  difficulty  to  detach  them:  When  placed  upon  the  mi- 
crometer they  measure  -Vth  of  an  inch  in  their  longitudinal,  and  -^th  of  an  inch  in  their 
transverse  diameter ;  a  few  being  somewhat  larger,  and  others  diminishing  in  size  to 
about  one  half  of  the  above  dimensions.  They  are  generally  placed  in  single  rows, 
parallel  to  the  muscular  fibres,  at  distances  varying  from  half  a  hne  to  a  line  apart 
'  The  existence  of  the  Entozoon  was  at  the  same  time  satisfactorily  determined  by  Mr.  Paget,  with  the 
assistance  of  Mr.  Brown  and  Mr.  John  Bennett,  at  the  British  Museum. 
