66 
Animal  Digestive  Ferments. 
(Am.  Jour.  Pharm 
\    February.  1902. 
fact  long  before  recognized,  as  we  have  seen,  that  the  stomach  was 
capable  of  self-digestion,  and  thus  the  tissue  of  the  whole  stomach 
or  the  mucous  membrane  converted  into  a  soluble  form.  This 
product  when  dried,  therefore,  contained  the  ferment  in  association 
with  the  peptones  produced  by  its  action.  It  is  at  this  time  unneces- 
sary to  state  that  the  products  of  peptic  action — the  peptonized 
proteids — possess  no  digestive  action  (although  at  one  time  there 
appeared  to  be  some  impression  of  this  current)  and  their  hygro- 
scopic nature  distinctly  unfits  them  as  a  vehicle  or  basis  for  com- 
mercial pepsin  if  associated  in  any  large  degree  with  the  ferment. 
It  may  be  said  that  all  pepsins  are  produced  by  processes  embody- 
ing principles  which  have  been  developed  by  scientific  research  and 
experiment  ;  at  present,  in  brief,  the  infusion  of  the  stomach  by 
such  methods  as  to  obtain  the  ferment  in  solution  as  free  as  possible 
from  associated  proteids,  or  else  by  heat  to  convert  the  paptic  glands 
into  complete  solution,  and  the  precipitation  of  the  enzyme  from 
this  solution  by  such  well-known  reagents  as  sodium  chloride, 
sodium  sulphate,  magnesium  sulphate,  etc.,  and  purification  by 
various  methods — dialysis,  etc. 
In  these  processes,  advantage  is  taken  of  the  fact  that  by  infusion 
of  the  gland  with  heat,  in  acidulated  solution,  the  whole  tissue  can 
not  only  be  converted  into  solution,  but  carried  forward  to  such  a 
point  as  to  yield  a  considerable  proportion  of  peptone,  this  not  being 
precipitable  by  the  reagents  mentioned  ;  so  that  by  this  means  the 
pepsin  as  precipitated  is  at  the  outset  of  a  much  higher  activity 
than  that  associated,  as  already  described,  with  a  large  amount  of 
albumoses. 
During  this  time  no  progress  in  the  utilization  of  the  pancreas 
ferments  at  all  comparable  to  that  in  pepsin  had  been  made,  very 
evidently  for  the  reason  that  scientific  observations  concerning  the 
varied  nature  and  action  of  the  pancreas  enzymes  had  either  escaped 
attention  or  failed  of  appreciation.  "  Pancreatine  "  seems  to  have 
been  made  by  methods  almost  identical  with  the  "  salt  process  "  for 
pepsin,  ignoring  the  fact  that  the  pancreatic  ferments  are  soluble  in 
salt  even  in  concentrated  solutions — not  precipitable  by  salt. 
Scheffer  criticized  this  method,  for  he  proved  sodium  chloride 
incapable  of  precipitating  pancreatin. 
In  spite  of  the  fact,  then,  that  the  pancreatic  ferments  had  been 
shown  to  possess  great  energy  in  the  conversion  of  starch  and  of 
