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MR.  R.  OWEN  ON  THE  STOMACH  OF  SEMNOPITHECUS. 
Ft.  In.  Lin. 
Length  along  the  greater  curvature,  beginning  at  the  left  extremity    2    7  0 
Length  along  the  lesser  curvature  100 
Greatest  circumference  (a  little  to  the  right  of  the  cardia)  ...  1  0  -  6 
Smallest  circumference  (at  about  two  inches  from  the  pylorus)  .    .         3  8 
This  stomach  may  be  regarded  as  consisting  of  three  divisions  :  1st,  a  cardiac  pouch, 
with  smooth  and  simple  parietes,  slightly  bifid  at  the  extremity;  2nd,  a  middle,  very 
wide  and  sacculated  portion ;  and  3rd,  a  narrow  elongated  canal,  sacculated  at  its  com- 
mencement, and  of  simple  structure  towards  its  termination.  The  latter  division,  from 
its  greater  vascularity  and  the  more  abundant  distribution  upon  it  of  the  nerves  of  the 
eighth  pair,  I  regard  as  the  true  digestive  stomach;  the  preceding  divisions  appear 
to  be  preparatory  receptacles  or  reservoirs. 
The  oesophagus  enters  into  the  left  or  cardiac  division,  which  is  separated  from  the 
middle  division  by  a  well-marked  constriction.  The  diameter  of  this  aperture  of  com- 
munication, when  the  stomach  has  been  forcibly  dilated,  does  not  exceed  2  inches : 
so  that  it  seems  highly  probable,  when  no  distending  force  is  operating  at  this  part, 
that  the  circular  fibres  which  surround  the  constriction  may,  by  the  act  of  contrac- 
tion, render  the  separation  complete,  and  thus  form  the  cardiac  pouch  into  a  distinct 
cavity.  A  similar  tendency  to  a  separation  of  the  cardiac  from  the  pyloric  moiety 
of  the  stomach  has  been  observed  to  exist,  in  a  greater  or  less  degree,  in  stomachs 
of  a  much  more  simple  structure,  as  in  those  of  Man  and  of  the  Carnivora.  It  is,  pro- 
bably, the  possession  of  tbis  power,  in  a  greater  degree,  that  enables  some  men  to 
regurgitate  at  will  a  small  portion  of  the  contents  of  the  stomach,  or  to  ruminate. 
Such  an  action  is  therefore  still  more  likely  to  take  place,  occasionally  at  least,  in  ani- 
mals which  possess  the  complicated  stomach  here  described :  and  there  is  a  provision 
in  these  stomachs  for  the  passage  of  ruminated  food,  or  such  as  is  of  a  fluid  or  easily 
digestible  nature,  directly  into  the  second  or  sacculated  division. 
A  ridge  is  continued  along  the  pyloric  side  of  the  cardiac  orifice  obliquely  to  the  fold 
in  the  middle  division,  which  is  situated  next  beyond  the  constriction :  a  second  ridge 
is  continued  from  the  right  side  of  the  cardia  into  the  lower  part  of  the  septum  that 
separates  the  cardiac  from  the  middle  compartment :  and  consequently  between  these 
ridges  a  shallow  canal  is  continued  from  the  oesophagus  to  the  middle  division  of  the 
stomach.  Supposing  the  circular  fibres  which  form  the  two  ridges  to  contract  simul- 
taneously with  those  forming  the  constriction  above,  then  the  communication  between 
the  asophagus  and  middle  division  of  the  stomach  would  be  cut  off ;  but,  on  the  other 
hand,  if  these  fibres  were  relaxed,  the  food,  and  especially  liquid  food,  would  pass  along 
the  oblique  canal  directly  into  the  middle  compartment. 
Longitudinal  fibres  are  continued  from  the  oesophagus  upon  the  cardiac  division ;  but 
they  gradually  converge  towards  its  left  extremity,  and  there  begin  to  be  collected  into 
the  narrow  band  which  traverses  nearly  the  whole  of  the  greater  curvature  of  the  stomach. 
