io6 
Animal  Digestive  Ferments. 
(  Am.  Jour.  Pharmr 
t      March.  1902. 
enzyme  has  now  become  much  employed  in  therapeutics  as  a  means 
of  administering  soluble  metallic  salts  (such  as  mercurials,  iodides, 
etc.),  bound  up  with  the  curd  of  milk  or  junket ;  also  used  in  the 
preparation  of  whey,  presenting  the  soluble  constituents  of  milk — 
non-coagulable  proteids,  salts  and  sugar — in  a  fluid  form  as  a  food 
for  the  sick  and  in  infant-feeding. 
The  topical  application  of  the  gastric  juice  so  convincingly  pre- 
sented at  the  very  outset  of  its  investigation,  after  long  escaping 
notice,  has  been  brought  to  renewed  attention  and  use  by  means  of 
artificial  gastric  juice  prepared  directly  from  the  fresh  stomach. 
This  interesting  and  important  therapeutic  utilization  is  based  upon 
the  well  demonstrated  facts  of  the  solvent  action  of  the  gastric 
juice  and  its  bactericidal,  healing  and  deodorizing  properties. 
Trypsin  is  also  now  employed  in  the  treatment  of  pus  cases,  espe- 
cially where  the  indications  are  for  the  application  of  a  solvent  of  a 
neutral  or  alkaline  reaction.  The  proteolytic  ferment  of  the  pan. 
creas  is  now  utilized  in  the  qualitative  conversion  and  quantita- 
tive adjustment  of  cow's  milk  to  normal  human  milk  in  digestibility 
and  in  the  ratio  and  content  of  nutritive  constituents. 
The  many  products  and  uses  of  the  peptic  and  pancreatic  fer- 
ments thus  brought  into  medicine  cannot  be  considered  here  in 
detail.  In  addition  to  the  directions  already  mentioned,  they  are 
utilized  as  therapeutic  agents  to  promote  the  efficiency  and  tolera- 
tion of  medicinal  agents,  especially  those  which  directly  disturb 
digestion  and  circulation  ;  as  aids  to  digestion  in  acute  and  chronic 
diseases,  and  in  various  forms  of  dyspepsia. 
From  our  present  knowledge  and  view  of  the  enzymes  of  the 
animal  digestive  secretions  we  know  that  the  proteolytic  enzymes 
do  not  exist  pre-formed  in  the  secreting  cell ;  it  may  be  said  that 
they  exist  as  "  zymogens."  It  is  uncertain  as  to  whether  there  is 
also  a  zymogen  of  the  starch-converting  and  curdling  and  emul- 
sifying ferments.  In  the  writer's  opinion,  the  preponderance  of 
evidence  at  the  present  time  is  that  this  has  not  been  established 
for  other  than  the  proteolytic  enzymes. 
In  their  chemical  constitution,  the  enzymes  are  presumably  identical, 
being  proteid,or  closely  akin  to  proteid  in  their  nature  and  behavior. 
As  we  have  already  seen,  some  of  the  most  recent  investigators 
have  declared  their  belief  that  they  are  of  the  nature  of  nucleo- 
proteids.    Whilst  we  have  the  statement  long  ago  made  by  Briicke 
