AnMLOrcti902.rm"}         Animal  Digestive  Ferments.  109 
any  known  way  related  to  an  acid  or  an  alkali ;  and  inasmuch  as 
alkalies  themselves  emulsify  fats,  it  is  difficult  to  differentiate  between 
the  action  of  the  ferment  and  the  alkali  in  any  conditions  in  which 
both  are  present. 
From  our  observations  we  are  strongly  inclined  to  the  view  that 
fats  in  contact  with  weak  acids  are  more  readily  emulsified  than 
pure  fats  ;  that  the  pancreas  ferment  has  the  power  of  splitting  up 
fats  is  certainly  undoubted. 
During  the  normal  conditions  of  digestion  it  would  seem  that  the 
distribution  of  fat  in  a  finely  divided  state  is  brought  about  (both 
by  chemical  and  physiological  means)  through  the  natural  commin- 
gling of  the  mass,  the  diffusion  of  the  fats  by  heat,  and  the  effect 
both  of  the  bile  and  pancreatic  secretions  upon  the  fat  as  so  con- 
tained in  the  acidulous  chyme. 
The  milk-curdling  ferment  of  the  pancreas  appears  to  be  in  every 
way  analogous  in  its  action  to  that  of  the  rennet  ;  in  practical 
operations,  however,  it  is  difficult  to  utilize  it  like  the  rennet  fer- 
ment, or  to  separate  it  for  study.  The  clot  of  milk,  as  originally 
formed  by  the  pancreas  juice,  is  absolutely  identical  in  apparent 
character  with  that  of  the  rennet  coagulum,  but  after  a  short 
time  the  caseine  and  other  milk  proteids  are  rapidly  attacked  by  the 
trypsin  of  the  pancreas  juice  and  gradually  reduced  to  solution, 
which  phenomenon  does  not  occur  in  contact,  however  prolonged, 
of  milk  with  the  rennet  ferment,  for  here  the  coagulum  gradually 
separates  in  a  mass  from  the  milk  serum.  The  pancreas  enzymes  are 
secreted  in  a  juice  which  is  exceedingly  complex  in  nature,  being 
rich  in  saline  constituents  (in  ash)  and  also  in  organic  matters,  those 
which  constitute  the  enzymic  and  related  bodies. 
Whilst  the  pancreatic  juice  is  said  by  many  observers  to  be  an 
alkaline  fluid,  we  invariably  find  that  infusions  from  the  gland,  pre- 
pared immediately  upon  being  taken  from  the  animal,  or  in  the  ordi- 
nary methods  of  procedure,  give  a  distinctly  acid  reaction  (with  no 
alkaline  reaction)  due,  we  believe,  to  acid  phosphates,  which  yield 
an  acid  ash.  The  fresh  gland  itself  invariably  gives  an  acid  reac- 
tion to  test  paper,  and  I  am  unable  to  account  for  this  except  upon 
the  hypothesis  that  the  juice  becomes  alkaline  either  at  the  time  of 
exudation  from  the  gland  or  by  some  changes  set  up  by  the  media 
with  which  it  thus  comes  in  contact.  It  is  known  that  these  fer- 
ments are  not  in  the  least  degree  dependent  upon  an  alkaline  reac- 
