AFebTuIvy,nimm'}      Analysis  of  the  Gastric  Contents.  ioi 
of  a  series  of  investigations  of  the  normal  digestion  which  I  have 
this  year  conducted  at  the  Harvard  Medical  School.74  The  subjects 
of  the  investigation  were  healthy  young  men  between  the  ages  of 
seventeen  and  thirty  years,  students  at  the  school.  The  number  of 
individuals  examined  was  fifty.  Such  cases  only  were  taken  as  had 
no  symptoms  of  digestive  disturbance  at  the  time  of  examination, 
and  no  history  of  chronic  or  intermittent  dyspepsia. 
The  investigation  was  conducted  in  the  following  manner  :  Each 
man  took  an  Ewald  test  breakfast,  consisting  of  one  baker's  roll  and 
300  c.c.  of  water  in  the  morning,  after  a  fast  of  twelve  hours.  One 
hour  later  the  stomach-tube  was  passed  and  the  gastric  contents 
expressed  by  the  Ewald  method  (page  32).  The  expressed  contents 
were  then  subjected  to  an  investigation  after  the  method  described 
in  this  paper,  summarized  on  page 
In  each  of  the  fifty  cases  the  following  determinations  were  made  : 
(1)  Total  quantity  of  mixed  contents. 
(2)  Total  filtrate. 
(3)  Presence  of  free  hydrochloric  acid. 
(4)  Presence  of  lactic  acid. 
(5)  Total  acidity. 
(6)  Total  hydrochloric  acid. 
(7)  Total  free  hydrochloric  acid. 
(8)  Total  combined  hydrochloric  acid. 
(9)  Total  organic  acids  and  acid  salts. 
(10)  Presence  of  starch,  of  erethrodextrin,  of  dextrin. 
(11)  Presence  of  native  proteids,  of  acid  albumin,  of  albumoses 
or  peptones. 
In  each  of  fifteen  cases,  in  addition  to  the  above,  these  determina- 
tions were  made  : 
(12)  Presence  of  butyric  acid. 
(13)  Presence  of  acetic  acid. 
(14)  Period  necessary  to  dissolve  5  milligrammes  of  coagulated 
egg  albumin  in  25  c.c.  of  filtrate  of  contents  at  400  C. 
(15)  Total  amount  of  acid  salts. 
(16)  Total  organic  acid. 
The  scheme  employed  in  the  analyses  was  that  given  in  the  sum- 
mary of  the  method  on  page  98. 
7  4  The  data  in  regard  to  the  pepsin  and  the  reunin  must  be  excepted  from 
this  statement.  These  are  taken  from  the  observations  referred  toon  pages 
43  and  44  of  the  last  number. 
