INFESTING  THE  MUSCLES  OF  THE  HUMAN  BODY. 
317 
but  continuing  of  uniform  diameter  from  that  point  to  the  opposite  extremity.  It  is 
only  at  the  larger  extremity  that  I  have  been  able  to  distinguish  an  indication  of  an 
orifice  ;  but  this  indication  has  been  so  constant  in  a  number  of  individuals,  examined 
under  every  variety  of  circumstance,  that  I  have  no  hesitation  in  ascribing  a  large  trans- 
verse linear  mouth  to  the  great  extremity,  which  I  therefore  consider  as  the  head. 
A  recently  extracted  worm,  seen  by  a  Wollaston's  doublet  before  any  evaporation  of 
the  surrounding  moisture  has  affected  its  integument,  presents  a  smooth  transparent 
exterior  skin  inclosing  a  fine  granular  and  flaky  substance  or  parenchyma ;  and  after 
carefully  testing  various  appearances  of  more  complex  organization,  that  have  on  dif- 
ferent examinations  presented  themselves,  I  now  believe  that  the  only  structure  that 
can  safely  be  ascribed  to  this  minute  Entozoon  is  the  simple  one  above  described.  It  is 
not  of  a  rigid  texture,  but  is  extremely  fragile,  and  exhibits  when  uncoiled  a  tendency 
to  return  in  some  degree  to  its  former  state. 
It  is  curious  to  watch  the  variety  of  deceptive  appearances  that  successively  present 
themselves  as  the  worm  dries  by  evaporation.  One  of  the  most  constant  is  a  succes- 
sion of  minute  transverse  rug<s,  especially  at  the  concave  sides  of  the  coils,  which  give 
a  finely  annulated  character  to  the  worm,  but  of  which  no  trace  can  be  perceived  in  the 
plump  recent  specimens  when  observed  by  a  good  doublet.  Another  appearance,  which 
is  more  difficult  to  be  accounted  for,  results  from  one  and  sometimes  two  longitudinal 
lines  extending  over  a  greater  or  less  proportion  of  the  body ;  but  these  are  not  to  be 
perceived  in  worms  examined  under  circumstances  least  liable  to  cause  deception.  As 
evaporation  proceeds,  the  wrinkling  of  the  integument  produces  an  appearance  of  the  body 
being  occupied  by  minute  tortuous  tubes,  and  a  beautiful  microscopical  effect  is  thus  ob- 
tained ;  but  the  fallacy  of  this  appearance  and  its  true  cause  are  easily  detected. 
The  test  of  coloured  food  could  nofe  be  applied  to  elucidate  the  form  of  the  digestive 
organs  in  the  present  instance :  there  was  not  any  indication  of  the  polygastric  struc- 
ture, which,  indeed,  was  hardly  to  be  expected,  since  it  does  not  exist  in  those  Ento- 
zooid  Infusoria  which  most  nearly  resemble  the  parasitic  species  in  question.  There 
was  no  appearance  of  the  parietes  of  an  alimentary  canal  floating  in  a  visceral  cavity 
and  distinct  from  the  integument  of  the  body,  as  in  the  higher  organized  Nematoid 
Entozoa  ;  nor  could  a  trace  of  an  orifice,  or  anus,  be  observed  at  the  smaller  extremity. 
I  have  been  equally  unable  to  detect  a  projecting  spiculum,  or  hook,  at  either  extremity, 
or  any  appearance  of  the  worm  having  been  torn  from  an  attached  cyst.  The  natural 
transparency  of  this  species  is  such  as  not  to  admit  of  a  doubt  as  to  its  wanting  the 
ovarian  and  seminal  tubes  and  other  characteristics  of  the  complicated  structure  of 
Filaria,  Ascaris,  and  the  Nematoid  Entozoa  generally. 
Three  species  of  small  Nematoid,  Worms  are  described  by  Zeder  as  inclosed  in  cysts 
or  capsules,  and  hence  were  termed  by  him  Capsularia.  Rudolphi,  however,  whose  au- 
thority on  this  subject  cannot  be  lightly  disregarded,  does  not  sanction  or  admit  this 
VOL.  I.  2  u 
