32 
Analysis  of  the  Gastric  Contents. 
(Am.  Jour.  Pharnx 
I    January,  1898. 
not  vary  in  the  period  between  one  hour  and  one  hour  and  a  hal<- 
after  ingestion  of  the  food,  to  an  extent  sufficient  to  affect  the  signi- 
ficance of  the  results. 
For  practical  work,  then,  the  contents  may  be  expressed  at  a 
period  between  one  and  one  and  one-half  hours  after  ingestion  of 
the  meal.29 
The  tube  used  is  a  soft  rubber  tube,  75  to  90  centimetres  in 
length.  The  end  of  this  tube  is  introduced  to  the  pharyngeal  end 
of  the  esophagus  and  swallowed  by  the  patient.  When  the  tube 
has  reached  the  stomach  the  contents  are  expressed.30 
The  simplest  method  of  expression  is  that  suggested  by  Ewakh 
This  consists  of  pressure  of  the  hand  upon  the  epigastrium,  and 
forced  vomiting  by  the  patient.  The  end  of  the  tube  is  moved  up 
and  down  in  the  stomach  during  the  expression.  As  a  rule,  practi- 
cally all  of  the  contents  can  be  obtained  by  this  method.  I  have 
repeatedly  tested  its  efficiency  by  following  the  expression  with 
siphonage  by  the  introduction  of  water. 
Another  excellent  method  of  expression  is  aspiration.  An  aspira- 
tion bulb,  with  a  short  rubber  tube  on  each  end,  is  attached  to  the 
stomach  tube.  By  alternate  compression  and  expression  of  the 
bulb,  under  the  control  of  appropriate  stopcocks,  the  contents  may 
be  successfully  aspirated.31 
The  expressed  contents  are  measured,  mixed  thoroughly  and  sub- 
jected to  the  chemical  analysis.    The  aim  of  this  analysis  is  : 
(1)  The  detection  of  the  presence  of  the  physiological  agents  of 
gastric  digestion — the  hydrochloric  acid,  pepsin  and  rennin. 
(2)  The  determination  of  the  quantity  of  these  agents. 
(3)  The  detection  of  certain  abnormal  products  peculiar  to  definite 
pathological  condition,  if  present — as  lactic  acid. 
(4)  The  testing  of  the  digestive  capacity  of  the  contents  as 
removed. 
The  reason  for  these  determinations  and  their  value  is  clear  from 
the  consideration  of  the  digestive  function  which  has  preceded. 
The  integrity  of  the  function  is  dependent  upon  the  presence  and 
sufficient  amount  of  the  physiological  agents. 
2  9  Cases  of  excessive  activity  of  digestion  are  reported  with  disappearance  of 
contents  within  one  and  one-half  hours. 
J0  The  distance  from  the  incisor  teeth  to  the  fundus  of  the  stomach  is  about 
23  to  26  inches. 
31  Boas  :  Magenkrankheiten,  s.  104. 
