146 
Manufacture  of  Pepsin. 
■  Am.  Jour  Pharm. 
1      March,  i»93. 
precipitant  instead  of  salt,  and  sulphurous  acid  has  been  added  dur- 
ing the  processes  of  manufacture,  to  prevent  decomposition  and  give 
the  operator  longer  time  for  effecting  perfect  clarification  of  the 
solution,  by  allowing  every  particle  of  undissolved  stomach  and 
suspended  mucus  to  deposit.  The  sulphurous  acid  destroys  much 
of  the  usual  animal  smell  always  present  in  pepsin  solutions,  and 
yields  an  almost  odorless  product. 
The  sulphate  of  soda  is  added  to  the  acidulated  pepsin  solution, 
as  described  in  Scheffer's  process,  at  a  temperature  of  about  940  F., 
when  saturated  sulphurous  acid  is  added,  so  as  to  give  the  mixture 
a  faint  sulphurous  acid  odor;  it  is  then  kept  at  this  temperature 
till  the  pepsin  separates,  care  being  taken  to  have  sulphurous  acid 
always  present  to  prevent  decomposition.  After  the  pepsin  has 
been  removed  the  sulphate  of  soda  mixture  is  allowed  to  cool,  when 
a  large  amount  of  sulphate  of  soda  will  crystallize  out,  and  may  be 
recovered  and  used  again.  The  pepsin  thus  prepared  is  tolerably 
free  from  peptones,  which  remain  in  the  sulphate  of  soda  solution, 
and  when  drained  and  pressed  it"  yields  a  tolerably  pure  and  active 
pepsin.  Any  sulphate  of  soda  present  may  be  removed  by  redis- 
solving  the  pressed  pepsin  in  water  acidulated  with  hydrochloric 
acid,  adding  sulphurous  acid,  and  dialyzing  the  mixture  in  the  usual 
way.  Pepsin  dialyzes  very  sparingly,  while  peptones,  sulphate  of 
soda,  common  salt,  syntonin,  etc.,  dialyze  much  more  readily  in  acid 
solutions.  When  sufficient  sulphate  of  soda  has  been  removed,  the 
undialyzed  portion  is  evaporated  in  vacuo,  either  to  dryness  and 
powdered,  or  sufficiently  concentrated  to  be  scaled  on  glass  plates. 
The  scales  of  this  pepsin  are  somewhat  opaque,  and  have  a  slight 
bitter  taste,  reminding  one  more  of  sodium  sulphate  than  of 
pepsin. 
Patents  for  Pepsin  Manufacture. — Some  of  the  above-mentioned 
improvements  in  the  manufacture  of  pepsin  have  been  the  subject  of 
patents.  C.  Jensen  took  out  a  patent  for  making  what  he  called 
crystal  peptone  pepsin.  He  describes  more  minutely,  and  lays  par- 
ticular stress  upon,  the  production  of  the  peptone,  the  impurity,  than 
the  pepsin  itself.  J.  LeRoy  Webber  patented  the  use  of  sodium 
sulphate  as  a  precipitant  and  of  sulphurous  acid  to  aid  in  clarifying 
and  dialyzing  the  impure  pepsin  solution;  while  J.  B.  Russell  pat- 
ented the  dialyzing  process  in  general  for  the  removal  of  peptones, 
soluble  salts  and  other  impurities.    Some  of  the  advantages  claimed 
