Aii).  Jour.  Pharni.\ 
March,  1893.  / 
Manufacture  of  Pepsin. 
141 
speak  well  for  the  purity  of  the  article;  in  fact,  the  principal  con- 
stituents of  it  are  mucus  and  epidermal  tissue,  as  might  be  expected 
from  the  mode  of  preparation. 
Bearing  in  mind  that  the  peptic  glands  are  imbedded  in  the  inner 
coating  of  the  stomach,  and  that  the  Pharmacopoeia  admits  a  great 
deal  of  impurity  or  insoluble  matter,  manufacturers  were  led  to  take 
the  inner  coatings  of  the  pig's  stomach,  stripped  from  the  less  active 
outer  fleshy  portion,  wash,  dry  and  powder  them.  Thus  was  pre- 
pared, in  a  very  simple  and  easy  manner,  a  kind  of  pepsin,  corres- 
ponding to  the  Pharmacopoeia  requirements,  and  found  to  possess 
very  great  strength.  This  process  has  been  much  improved  and 
perfected ;  it  is  now  extensively  carried  out  by  some  houses  in 
America  and  the  product  sold  in  the  market  as  insoluble  pepsin.  The 
fresh  pigs'  stomachs  are  cleaned  and  the  inner  coatings  stripped  off ; 
these  coatings  or  skins  are  then  trimmed  from  all  adhering  fat,  again 
thoroughly  washed  and  scrubbed  in  cold  water,  and  when  perfectly 
clean  and  free  from  mucus  and  blood,  they  are  packed  in  barrels 
filled  with  cold  water,  with  lumps  of  ice  on  top,  and  left  to  stand 
overnight,  to  still  further  remove  any  blood  or  impurities.  Next 
morning  they  are  again  washed  and  scrubbed.  Thus  washed  until 
free  from  mucus  and  blood,  they  appear  quite  white  and  clean.  The 
membranes  are  then  spread  out  on  linen  sheeting  extended  over 
frames,  care  being  taken  to  prevent  overlapping,  and  are  quickly 
dried  at  a  low  temperature,  in  a  properly  arranged  drying  room. 
They  dry  to  horny  semi-transparent  sheets  which,  when  coarsely 
powdered,  are  treated  with  benzol,  ether  or  chloroform,  to  remove 
fat,  then  dried  again  and  reduced  to  a  very  fine  powder.  It  is  not 
advisable  to  carry  the  powdering  too  far,  but  best  to  collect  only 
the  first  few  siftings,  and  to  leave  an  appreciable  amount  of  residue. 
The  first  siftings  possess  the  greatest  digestive  power,  the  powder 
obtained  afterwards  being  less  active  and  containing  most  of  the 
inert  epidermal  tissue.  The  siftings  have  therefore  to  be  tested  from 
time  to  time,  and  pulverization  stopped  as  soon  as  the  powder 
becomes  deficient  in  strength.  It  is  an  important  fact  that  notwith- 
standing the  long  and  repeated  washings  of  the  coatings  of  the 
stomach,  the  pepsin  ultimately  obtained  by  this  process  is  of  great 
strength,  I  grain  dissolving  readily  about  2,000  grains  of  finely 
divided  coagulated  albumin.  There  can  be  no  doubt  that  during 
the  washing  all  the  ready  formed  pepsin  must  have  been  removed, 
