Am.  Jour.  Pharm.1 
March,  1902.  / 
Animal  Digestive  Ferments, 
107 
and  recently  by  Oppenheimer  that  a  proteolytic  ferment  possessing 
the  power  to  dissolve  fibrin,  but  failing  to  give  the  proteid  reactions 
had  been  isolated,  it  is  very  singular  that  others  have  not  verified 
this,  especially  when  we  consider  the  careful  attention  the  subject 
has  received  from  the  most  eminent  physiologists  and  chemists. 
The  enzymes  are  all  soluble,  destroyed  when  in  solution,  by  heat; 
resistant  to  high  temperature  (ioo°  C.)  when  in  a  dry  form,  and, 
with  probably  one  or  two  exceptions,  non-diffusible. 
If  we  prepare  an  infusion  of  the  peptic  gland  and  submit  this  to 
heat  under  the  physiological  conditions  necessary  to  convert  into 
peptone  all  the  associated  proteids  digestible  by  the  enzyme,  and 
remove  these  by  dialysis,  we  shall  still  find  this  infusion  to  contain 
a  non-dialysable  body,  exerting  peptic  action,  precipitable  upon 
boiling.  This  precipitate,  so  obtained,  washed  and  submitted  to 
pepsin-hydrochloric  acid  digestion,  proves,  absolutely  refractory  to 
pepsin  action.  This  substance  has  the  properties  of  a  proteid  and 
Contains  nucleic  acid.  Identical  results  are  likewise  obtained  with 
the  pancreas  enzymes, 
Whether  the  enzymes  then  are  nucied-proteids,  or  whether  nuclein 
may  be  the  "  material  substratum  "  of  the  enzymes,  cannot  at  pres- 
ent be  stated.  We  have  not  obtained  an  enzyme  in  any  form  as 
yet  which  is  not  in  its  constitution  and  character  analogous  to  pro- 
teid. 
The  gastric  juice  is  generally  held  to  contain  two  distinct 
enzymes,  although 'some  writers  have  recently  suggested  that  both 
the  curdling  and  proteolytic  action  are  manifestations  of  the  one 
enzyme  under  different  conditions.  This  seems  very  doubtful  from 
our  own  observations,  and  is  without  analogy  in  the  behavior  and 
functions  of  the  ferments  in  general.  Whilst  pepsin  is  present  in 
the  stomach  of  all  ruminant  and  carnivorous  animals,  we,  however, 
regard  the  milk-curdling  ferment  as  particularly  a  constituent  of 
the  nursling  animal ;  for  we  have  observed  that  in  the  calf  and 
other  animals  the  curdling  activity  steadily  diminishes  in  direct 
ratio  to  the  growth  of  the  animal. 
The  enzyme  becomes  potential  or  vitalized  only  at  the  momei^of  - 
its  discharge  or  extrusion  from  the  cell.    Pepsinogen  is  not  feaund 
up  with  the  acid,  for  the  enzyme  may  be  freed  from  hydrochloric 
acid  without  destroying  its  vitality;  nevertheless,  there  is  a  strong 
chemical  and  physiological  tie  between  them. 
