576  Action  of  Digedive  Ferments  upon  Drugs.   { ^%ov"^88?™' 
precipitate  was  found  to  consist  of  calcium  carbonate^  with  a  consider- 
able quantity  of  the  diastastic  ferment  carried  down  by  the  precipitated 
chalk.  This  precipitate^  carefully  w^ashcd,  was  found  to  possess  strong 
amylolytic  but  no  pi'oteolytic  or  emulsifactive  power. 
I  should,  therefore,  think  that  the  arabin  of  gum  acacia  remained 
unaffected  by  tlie  processes,  and  that  the  ])eptonizing  change  was 
wrought  upon  some  slight  impurity  of  gum,  possibly  containing  nitro- 
gen ;  this  point,  however,  is  reserved  for  further  investigation. 
Closely  allied  in  physical  character  to  gum,  and  holding  an  interme- 
diate place  between  foods  and  medicines,  are  the  mucilages  obtained 
from  Irish  and  Iceland  moss.  On  Irish  moss  the  alkaline  extract  of 
the  pancreas  seeuied  to  exert  very  little  action.  The  proteolytic  fer- 
ment of  the  pancreas  extracted  with  acids  soon  destroyed  the  viscidity 
of  the  mucilage,  and  divided  the  jelly  into  soluble  and  insoluble  por- 
tions. These  results  were  also  obtained  by  the  digestion  of  chondrus 
jelly  with  solution  of  pepsin;  the  products  resembled  and  perhaps  were 
identical  with  parapectin  and  pectic  acid. 
Cetraria,  or  Iceland  moss,  behaved  somewhat  differently.  A  jelly 
of  this  substance  retained  its  color,  but  became  flocculent  when  acted 
upon  by  the  gastric  ferment.  On  the  other  hand,  the  pancreatized 
jelly  retained  more  of  its  viscidity,  became  deeper  colored,  and  gave  a 
deposit  of  yellowish-white  flakes.  These  flakes  under  the  microscope 
were  found  to  consist  of  noncrystalline  masses  (pectic  acid  ?). 
The  digestives  were  found  to  produce  or  accelerate  the  pectic  fer- 
mentation by  some  experiments  upon  the  pectin  of  the  turnip. 
I  must  now  leave  the  consideration  of  this  part  of  my  subject  and 
call  your  attention  to  the  action  of  the  ferments  upon  more  definite 
substances.  The  acidulated  extract  of  the  gastric  juice  decomposed  a 
watery  solution  of  salicin  very  slowly  and  imperfectly  ;  saliretin  was 
formed,  but  it  was  associated  with  undecomposed  salicin.  On  the 
other  hand,  the  pancreatic  ferment  split  up  the  salicin  into  saligenin 
and  glucose,  and  the  saligenin  separated  by  solution  in  ether  and  sub- 
sequent crystallization  was  obtained  in  the  form  of  white  laminae  or 
scales. 
A  well-washed  sample  of  jalapin  remained  intact  after  digestion 
with  the  pepsin  solution,  but  pancreatic  digestion  withdrew  a  copper- 
reducing  substance  from  the  jalapin. 
Santonin  was  unaffected  by  gastric  and  pancreatic  solutions. 
A  solution  of  tannin  treated  with  the  acid  pepsin  solution  became 
