"^"sepriSs™'}  Peptone  in  the  Animal  Body.  445 
celliilar  organs,  while  others  have  deemed  it  to  occur  in  the  blood 
itself. 
The  author  does  not  agree  with  either  of  these  views,  owing  to  the 
circumstances  that  when  peptone  is  introduced  into  the  circulation  in 
some  other  way  than  by  absorption  from  the  intestine,  by  direct  injec- 
tion, for  instance,  the  greatest  part  escapes  unchanged  in  the  urine. 
This  would  point  to  the  intestinal  mucous  membrane  itself  as  the 
place  of  actual  transformation. 
In  the  first  i)lace,  it  was  necessaay  to  ascertain  the  normal  distribu- 
tion of  peptone  in  the  body  at  successive  stages  of  the  process  of 
digestion,  so  as  to  exclude  the  possible  influence  of  other  organs  besides 
the  intestine  and  the  blood,  on  the  destiny  of  peptone. 
The  experiments  were  made  upon  dogs  fed  upon  flesh,  which  was 
killed  at  different  periods  of  the  digestive  process  by  means  of  blood 
letting.  The  amount  of  peptone  was  then  determined  in  the  various 
organs.  The  blood,  heart,  lungs,  stomach,  large  and  small  intestines, 
liver,  pancreas,  spleen,  mesenteric  glands,  mesentery,  kidneys,  and 
brain  were  severally  examined.  The  method  followed  by  the  author 
is  given  in  the  present  and  also  in  a  previous  memoir  (1881),  to 
which  the  reader  is  referred  for  details. 
The  results  of  these  experimental  observations  showed  that  only  in 
one  locality  was  peptone  to  be  constantly  found,  in  the  intestinal 
mucous  membrane.  The  proportions  varied  in  different  parts  of  the 
alimentary  tract. 
In  the  stomach  the  amount  of  peptone  did  not  appear  to  have  any 
ratio  to  the  progress  of  digestion,  save  that  in  the  case  of  long  depri- 
vation of  food  it  sank  to  the  limits  of  recognition.  In  the  small  intes- 
tines, on  the  contrary,  a  regular  increase  in  the  amount  of  peptone  up 
to  the  eleventh  hour  after  food  was  given  was  observed,  followed  by  a 
diminution ;  the  formation  of  peptone  in  the  small  intestines  was  pari 
passu  with  its  absorption  by  the  mucous  layer.  These  observations 
agree  with  those  of  Schmidt-Miilheim,  and  likewise  with  those  of 
Panum  and  Falck,  in  which  the  excretion  of  urea  in  flesh-fed  dogs 
attained  its  maximum  at  the  same  period.  This  analogy  between  the 
formation  of  peptone  and  excretion  of  urea  would  favor  the  acceptance 
of  the  view  that  much  of  the  absorbed  peptone  is  at  once  broken  up 
into  its  final  products. 
The  total  amount  of  peptone  in  the  alimentary  walls,  including 
stomach  and  intestines,  is  more  than  double  that  present  in  the  blood 
