A  jan^yPih898.m'}     Analysis  of  the  Gastric  Contents,  29 
reached  from  one  to  one  and  one-half  hours  after  an  Ewald  meal, 
from  two  to  three  hours  after  a  Leube  meal. 
Upon  the  facts  contained  in  this  review  of  the  function  of  gastric 
digestion  is  based  the  method  of  investigation.  It  is  clear,  from 
this  review,  that  the  important  points  to  be  investigated  are  :  The 
presence  and  amount  of  the  physiological  agents  of  digestion  ;  the 
evidence  of  their  action  upon  the  food ;  and  the  presence  or  absence 
of  certain  abnormal  products.  We  have  found  that  the  time  of  the 
appearance  of  these  agents  and  the  amounts  of  them  secreted  vary 
according  to  the  quantity  and  quality  of  the  food  ingested.  To 
judge  of  the  status  of  these  agents  in  a  given  case,  therefore,  we 
must  obtain  the  contents  of  the  stomach  in  that  case  at  a  given  time 
after  a  definite  meal,  subject  these  contents  to  a  systematic  examina- 
tion, and  compare  the  results  of  this  examination  with  standard 
results  obtained  from  an  investigation  of  the  contents  of  the  normal 
stomach  in  a  series  of  cases  under  the  same  conditions. 
The  first  step  in  the  development  of  the  method  is  the  choice  of 
the  meal.  This  test  meal  should  contain  the  ordinary  elements  of 
mixed  food,  that  is,  proteids,  albuminoids,  carbohydrates  and  fats. 
It  should  also  contain  none,  or  as  small  amounts  as  possible,  of  those 
substances  the  production  of  which  is  peculiar  to  the  pathological 
conditions  of  the  stomach,  that  is,  lactic,  butyric  and  acetic  acids. 
Of  the  meals  which  have  been  proposed  as  test  meals,  we  may 
mention  those  of  Ewald,18  of  Leube  and  Riegel,19  of  Reichman,20  of 
Jaworski,21  of  Klempere,22  of  Boas.23  Two  of  these  only  are  in 
common  use  for  general  work,  that  of  Ewald  and  that  of  Leube  and 
Riegel. 
The  Ewald  test  breakfast  consists  of  one  baker's  roll,  weight 
about  35  grammes,  and  300  c.c.  of  water,  or  of  tea  without  milk  or 
sugar.  According  to  Konig's  analysis,  such  a  roll  contains  7  per 
cent,  of  nitrogen,  y2  per  cent,  of  fat,  4  per  cent,  of  sugar,  and  52-5 
per  cent  of  non-nitrogenous  extractive  substances,  to  which  1  per 
cent,  ash  must  be  added.24 
18  Klinik  der  Verdauungskrankheiten,  Vol/ II,  s.  14. 
1 9  See  below. 
20 Reichman 's  meal  :  meat  fonder  30  grammes,  1  roll,  water  200  c.c,  salt  2 
grammes. 
21  Zeitschr.  klin.  Med.,  Bd.  XI,  s.  275. 
22  Ewald:  Berl.  klin.  Woch.,  1886,  No.  3. 
23  Deutsch.  med.  Woch.,  No.  39,  1893. 
24  Ewald  :  Loc.  cit. 
