Am.  Jour.  Pharni.  ^ 
M;ay,  1892.  J 
Chemistry  of  Digestion. 
243 
liquid,  and,  when  it  exists  there,  its  proportions  are  very  irregular. 
We  caimot,  therefore  base  clmical  researches  on  the  dosage  of  the 
free  HC1. 
(4)  Organic  combined  hydrochloric  acid  (C).  Its  variations  are 
very  regular,  and  when  the  test  meal  is  mixed  they  go  on  parallel 
to  those  of  the  total  chlorine.  When  distilled  water  has  been  given, 
C  increases  very  little,  or  remains  almost  nil. 
(5)  The  acidity  (A)  is  always  very  much  greater  than  the  free  HC1 
in  the  normal  digestion  of  man ;  further,  it  is  very  near  the  sum  of 
H-fC, — that  is  the  free  HQ  and  combined  organic  hydrochloric 
acid.  This  fact  favors  the  .  supposition  that  the  gastric  liquid  is 
acidified  by  combined  HC1.  After  a  mixed  meal,  in  the  dog,  the 
maximum  acidity  corresponds  to  the  maximum  of  the  chlorine  ele- 
ments, but  the  decrease  of  the  acidity  is  less  rapid  than  that  of  those 
elements;  there  are,  therefore,  at  the  end  of  digestion  other  acid 
elements  than  free  HC1  and  combined  organic  CI  elements,  whose 
nature  is  not  known. 
Hence  it  is  a  great  mistake  to  consider  the  total  acidity  as  due 
essentially  to  free  HCl,  for  (1)  this  acid  often  fails;  (2)  hydrochloric 
acid  may  be  combined  with  organic  albuminoid  matters;  (3)  organic 
acid  may  be  present ;  (4)  there  may  be  a  small  quantity  of  phos- 
phates. The  quantities  1,  3,  and  4,  represent  only  the  smallest  part 
of  the  acidity,  of  which  the  greater  part  is  due  to  hydrochloric  acid 
combined  with  organic  matters  in  solution  ;  (4)  if  into  the  juice  of 
meat  obtained  by  expression,  and  already  acid,  we  pour  a  known 
quantity  of  not  too  strong  HCl,  at  the  end  of  a  very  short  time  the 
color  reactions  of  the  latter  are  no  longer  produced,  the  liquid  evap- 
orated at  ioo°  or  no°  no  longer  allows  HCl  to  escape.  MM. 
Hayens  and  Winter  think  that  the  albumen  dissolved  in  the  gastric 
juice  is  found  in  the  state  of  hydrochlorate  of  an  amido  acid  of  the 
,  ,       .       /NH2  HCl. 
general  formula  R  <  qq  qh 
If  we  admit  that  the  combined  HCl  exists  in  the  gastric  juice  in 
the  form  of  salts  of  amido  acid,  the  total  acidity  A  of  the  gastric  juice, 
less  the  free  HCl  (H)  ought  to  be  equal  to  the  combined  HCl  (C) 
when  there  is  another  acid  present.  That  is  to  say,  we  should  have 
A— H 
— ^ —  =  1.  This  relation  a  will  be  greater  than  1,  when,  beside 
hydrochloric  acid,  organic  acids  are  present,  it  will  be  less  than  1 
