144 
Manufacture  of  Pepsin. 
Am.  Jour.  Ptaarm. 
March,  1893. 
the  pressure  may  be  increased.  Should  the  mass  be  too  salt,  it  may 
be  mixed  with  an  equal  quantity  of  a  mixture  of  2  parts  of  water 
and  1  part  alcohol,  allowed  to  stand  for  some  time,  drained  and 
pressed  as  before.  After  being  pressed  as  dry  as  possible,  the  pep- 
sin is  taken  out  of  the  cloth,  crumbled  up,  placed  in  shallow  trays, 
and  dried  at  a  temperature  of  not  higher  than  ioo°  F.  When  dry,  it 
is  coarsely  powdered,  treated  with  benzol,  ether  or  chloroform,  to 
remove  fat,  again  dried,  and  reduced  to  the  finest  powder  possible. 
It  sometimes  happens  that  after  taking  all  the  precautions 
described  the  pepsin  does  not  rise  well,  and  most  of  it  remains  in 
solution.  By  allowing  such  a  liquor  to  stand  longer,  or  by  adding 
a  fresh  portion  of  stomach  liquor  and  more  salt,  the  whole  of  the 
pepsin  may  be  recovered  in  good  condition.  It  is  seldom  necessary 
to  throw  a  liquor  away  after  removing  the  pepsin,  but  by  allowing 
it  to  stand  till  it  has  become  perfectly  clear,  the  supernatant  brine 
may  be  syphoned  off,  and  the  flocculent  sediment  collected. 
Scale  and  Crystal  Pepsins. — Besides  these  powdered  pepsins  more 
elegant  preparations  known  as  scale  and  crystal  pepsins  are  in  the 
market,  some  of  these  being  of  very  good  quality  and  strength. 
These  preparations  are  made  entirely  from  the  inner  coatings  of  the 
pigs'  stomachs.  In  an  operation  with  the  inner  coatings  of  125 
stomachs,  weighing  about  65  pounds,  they  were  washed  and  soaked 
well  in  cold  water,  to  remove  mucus,  blood  and  other  impurities, 
freed  from  adhering  fat,  and  then  passed  through  a  mincing  machine. 
The  minced  mass  was  placed  in  a  digester  with  80  pounds  of  distilled 
water  and  16  ounces  of  strong  hydrochloric  acid,  and  the  whole 
digested  at  about  ioo°  F.  The  mixture  was  stirred  all  the  while, 
care  being  taken  not  to  let  the  temperature  rise  above  1120  F.,  and 
the  digestion  continued  till  the  particles  of  stomach  were  dissolved. 
About  six  hours  are  requisite  to  effect  complete  solution.  The  pieces 
of  minced  stomach  swell  up  at  first,  and  form  a  slimy  grayish-white 
coherent  mixture.  This  sliminess  increases  till  the  whole  is  con- 
verted into  a  uniform  transparent  glairy  magma.  By  continuing 
the  digestion  and  stirring,  the  mass  loses  its  homogeneity,  breaks 
up,  becomes  thinner,  and  fine  red  particles  separate.  When  this 
condition  is  attained  digestion  is  stopped,  and  the  solution  allowed 
to  cool  and  deposit ;  before  leaving  it  to  settle,  it  is  advisable  to  add 
2  ounces  of  chloroform,  and  some  sulphurous  acid  to  the  mixture. 
It  is  then  left  to  stand  undisturbed  overnight.     The  amount  of 
