AFebr°UwyPi8a9r8m'}      Analysis  of  the  Gastric  Contents.  99 
decinormal  soda-solution  more  delicate  than  the  Congo  (-036  to  -072 
gramme  per  mille).  In  many  cases  the  alizarin  test  is  not  clear,  and 
in  such  cases  the  Congo  test  must  be  relied  upon.  (See  last  num- 
ber of  this  Journal,  page  38). 
Continue  to  add  decinormal  solution  until  a  pinkish-red  color  ap- 
pears permanently  in  the  mixture.  The  reading  at  this  point  indi- 
cates the  total  acidity  [A).  Subtract  B  from  A  =  total  combined 
acid  (C).  Add  D  to  C=  total  secreted  HC1  (E).  Subtract  D  from 
B  —  total  organic  acids  plus  acid  salts  {F\  Repeat  this  analysis 
to  this  point  with  a  fresh  portion  of  contents. 
(8)  Test  10  c.c.  of  the  contents  for  acid  salts  by  Leo's  method. 
Estimate  free  acids  plus  acid  salts  in  10  c.c.  of  contents  after  the 
addition  of  1  gramme  calcium  carbonate  (see  page  41).  Subtract 
total  acid  salts  (G)  from  this  estimate  of  the  total  free  acids  plus 
acid  salts  (B2)  =  total  free  acids  (H).  Subtract  total  free  HC1  (D) 
from  total  free  acids  (77)  —  total  organic  acids  (K). 
(9)  Place  50  milligrammes  of  coagulated  white  of  egg  in  25  c.c. 
filtrate  of  contents  at  400  C,  and  record  time  of  disappearance  of 
egg- 
(10)  Test  for  rennin  and  rennet  zymogen  by  the  tests  given  on 
page  44). 
(11)  If  free  HC1  be  absent,  test  for  pepsin  by  the  Hammerschlag 
method  (page  43). 
(12)  If  free  HCl  be  absent,  estimate  the  total  combined  HC1  by 
the  Mintz  method  (page  36). 
The  record  for  the  second  analysis  for  quantitative  estimation  of 
the  total  acidity,  total  for  HCl,  etc.,  may  be  taken  as  the  final  re- 
cord. The  quantitative  tests  for  each  of  these  substances  may  be 
made  in  separate  portions  of  contents,  if  desired. 
This  is  a  summary  of  the  complete  chemical  analysis  of  the 
gastric  contents,  as  far  as  such  analysis  is  suited  to  chemical  work. 
It  is  unnnecessary,  in  many  cases,  to  apply  the  complete  analysis. 
If  a  given  contents  shows  free  HCl  present,  no  lactic  acid,  normal 
total  acidity,  and  a  normal  period  of  digestion  of  the  egg  albumin, 
it  is,  as  a  rule,  safe  to  conclude  that  no  abnormality  which  can  be 
discovered  by  further  chemical  analysis  is  present.  At  the  same 
time  a  more  complete  insight  into  the  particular  condition  of  'the 
digestive  apparatus  in  such  cases  may  frequently  be  obtained  by  the 
estimation  of  the  separate  acid  factors  or  the  full  analysis.  Where 
