AFebruary?if98m*}      Analysis  of  the  Gastric  Contents.  97 
of  T7¥  per  mille  free  hydrochloric  acid,  or  1  to  2  per  mille  combined 
hydrochloric  acid.  In  the  normal  stomach  the  action  of  the  bacillus 
is  inhibited  by  the  increasing  acidity,  before  any  appreciable  fermen- 
tation can  be  produced  by  the  few  bacilli  swallowed  with  the  food. 
Where,  in  pathological  conditions,  the  secretion  of  hydrochloric 
acid  is  absent  or  slight,  and  the  presence  of  stenosis  or  dilatation  with 
resulting  stasis  of  the  contents  gives  a  long  period  for  action  to  the 
bacillus,  great  multiplication  of  the  bacilli  and  fermentation  of  large 
amounts  of  lactic  acid  occur.73  This  condition  is  most  associated 
with  carcinoma  of  the  stomach,  where  the  combination  of  the  con- 
ditions of  atrophy  of  the  secreting  structures  and  of  stenosis  is 
most  common.    It  may  occur  in  other  conditions.73 
Butyric  acid  is  not  a  constituent  of  the  gastric  juice.  It  is  formed 
from  carbohydrate  and  milk  foods  by  the  action  of  several  bacilli, 
among  them  the  bacillus  butyricus.  Physiologically  it  may  occur 
in  the  gastric  contents  after  the  ingestion  of  large  amounts  of  carbo- 
hydrate foods  or  milk.  After  an  Ewald  meal  the  amount  of  butyric 
acid  is  never  enough  in  the  normal  stomach  to  appear  in  the  tests 
one  hour  after  ingestion.  In  pathological  conditions,  however,  lactic 
and  butyric  acids  may  be  present  in  the  contents. 
The  tests  of  butyric  acid  are  as  follows:  10  c.c.  of  the  contents 
are  shaken  with  50  c.c.  of  ether,  the  ether  drawn  off  and  evaporated, 
and  the  residue  dissolved  in  water,  To  this  aqueous  solution  lumps 
of  calcium  chloride  are  added.  If  butyric  acid  is  present  in  amount 
sufficient  to  be  of  pathological  significance,  globules  of  the  acid  will 
separate  out  in  the  solution.  Butyric  acid  may  be  discovered  also 
by  adding  to  the  contents  alcohol  and  sulphuric  acid,  and  heating. 
If  butyric  acid  be  present,  the  pineapple  odor  of  its  ethyl  ester  will 
be  perceived. 
Butyric  acid,  when  present  in  the  amount  of  y2  gramme  per  mille, 
gives  a  tawny-yellow  color  with  ferric  chloride.  Where  the  acid  is 
present  in  considerable  amounts,  it  may  be  distinguished  by  the 
odor  of  the  contents. 
Acetic  acid  may  occur  in  the  gastric  contents  in  the  presence  of 
abnormal  fermentation  of  carbohydrates.  It  is  never  present  in  the 
normal  contents  after  an  Ewald  breakfast.  It  is  produced  by  the 
action  of  a  unicellular  organism  (the  Mycoderma  aceti)  upon  the 
food. 
7  3  Hammerschlag  :  Archiv.  f.  Verdauungskrankheiten,  Bd.  II,  H.  I. 
