102  Analysis  of  the  Gastric  Contents.  {^irZiyM^' 
In  testing  for  free  HQ,  all  four  of  the  reagents  mentioned  in  the 
detail  of  the  method  were  used  in  order  to  test  their  relative  delicacy 
and  applicability. 
The  test  used  for  lactic  acid  was  the  De  Jong  test. 
The  much-used  Uffieman  test,  as  also  the  Penzolt  modification  of 
this,  were  both  used  in  each  case,  in  order  to  test  the  relative  accu- 
racy of  these  tests  by  the  De  Jong. 
The  quantitative  estimations  were  made  in  each  case  both  upon 
the  mixed  contents  and  upon  the  filtrates.  The  method  used  in  the 
quantitative  work  is  that  detailed  in  the  description  as  the  color- 
analysis  method  (page  37). 
It  is  clear  that  the  results  obtained  in  this  way  are  of  value  chiefly 
for  comparative  work.  For  example,  the  estimation  of  the  total 
free  hydrochloric  acid  is  slightly  less  than  the  actual  amount  pres- 
ent, as  the  limits  of  the  Gunzberg  reaction  test  are  at  best,  0-05 
gramme  per  mille.  In  the  estimation  of  the  total  organic  acids  plus 
acid  salts,  by  the  subtraction  of  the  total  free  hydrochloric  acid 
from  the  total  free  acids  plus  acid  salts,  this  0*05  gramme  per  mille  of 
HC1  must  therefore  be  included  in  the  total  of  organic  acids  plus 
acid  salts,  making  this  total  slightly  too  high.  But  such  an  error 
in  the  absolute  amounts  does  not  affect  the  value  of  the  results  for 
comparative  work,  since  this  error  is  a  constant  in  all  results 
obtained  by  this  method. 
The  results  in  the  fifty  cases  fall  within  regular  and  fairly  circum- 
scribed limits  admitting  of  a  definite  classification. 
The  qualitative  results,  as  regards  the  mineral  and  organic  acids, 
are  absolutely  regular. 
The  quantitative  results  show  a  fairly  wide  range  of  variation  in 
the  different  cases  ;  excepting  in  one  case  (Case  17),  however,  these 
results  correspond  to  a  definite  type. 
The  summary  of  results  in  the  cases  is  as  follows  : 
(1)  Total  quantity  of  contents:  mean,  no  c.c. ;  minimum,  35 
c.c;  maximum,  220  c.c.  Twenty-five  cases  gave  a  quantity  of  100 
c.c.  or  more. 
(2)  Total  quantity  of  filtrate:  mean,  no  c.c. ;  minimum,  20  c.c; 
maximum,  140  c.c.    Eight  cases  gave  100  c.c.  or  more. 
(3)  Free  hydrochloric  acid.    Present  in  all  cases. 
(4)  Lactic  acid.    Present  in  no  case. 
The  Uffleman  test  was  obtained  from  the  crude  filtrate  in  eight 
cases. 
