Am.  Jour.  Pharm. 
March,  1902. 
Animal  Digestive  Ferments. 
1 1 1 
The  behavior  of  the  various  digestive  juices  toward  each  other, 
their  related  role  in  the  digestion  process,  has  been  the  subject  of 
immense  research,  theory  and  conjecture,  and  opinions  of  the  widest 
possible  variance  have  been  expressed.  This  variance  can  be 
accounted  for  in  a  great  degree  by  the  nature  and  oftentimes  incon- 
clusive methods  of  experiment ;  the  fact  is  sometimes  lost  sight  of, 
that  the  contact  of  these  enzymes  in  solution  and  in  various  media, 
acid,  neutral  or  alkaline,  introduces  conditions  foreign  to  those  met 
with  in  the  alimentary  tract. 
The  first  and  only  positive  conclusion  to  be  drawn  from  such 
experiments  is,  that  solutions  of  mixed  ferments  which  are  found  to 
exert  injurious  effect  upon  each  other,  under  the  ordinary  conditions 
to  which  they  must  be  submitted  in  use,  should  not  be  prepared  and 
presented  as  pharmaceutical  products. 
We  have  particularly  noted  that  the  behavior  of  free  hydrochloric 
acid  towards  the  ferments  is  distinct  from  that  of  the  gastric  juice 
itself  where  the  acid  exists  in  peculiar  physiological  relation  to  the 
various  proteids.  This  is  the  common  observation  of  physiologists. 
Free  hydrochloric  acid  behaves,  for  instance,  very  differently  to 
starch  digestion  (of  any  diastase)  from  the  equivalent  amount  of 
acid  as  combined  in  the  gastric  juice. 
The  fact  that  diastase  is  injured  in  solution  by  maceration 
with  pepsin  and  hydrochloric  acid  does  not  make  it  by  any  means 
conclusive  that  the  saliva  is  useless  in  the  stomach  ;  for  it  must 
be  considered  that  the  various  juices  from  the  salivary,  gastric, 
and  pancreatic  glands  are  secreted  under  the  stimulus  of  food, 
are  brought  together  mingled  with  foods  of  a  complex  nature 
and  in  various  stages  of  digestive  conversion ;  and  that  the 
various  constituents  of  the  juices  and  of  the  foods  have  important 
functions  in  the  whole  digestive  scheme.  Furthermore,  there  are 
various  stages  of  activity  and  reactions  of  media  in  the  normal 
progress  of  digestion. 
In  the  therapeutic  use  of  the  digestive  ferments  we  are  by  no 
means  dealing  with  normal  digestion,  nor  are  we  restricted  solely  to 
one  period  or  one  method  in  the  introduction  of  the  various  enzymic 
agents  into  the  economy.  This  subject  is  of  very  great  importance 
as  regards  the  therapeutic  use  of  the  digestive  ferments. 
The  writer  dealt  with  this  subject  in  a  pamphlet  on  the  "  Extract 
of  the  Pancreas  and  its  Uses,"  in  1 883,  and  referred  to  his  experiments 
