ON  THE  PREPARATION  OF  LIQUID  PEPSIN. 
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fully  satisfied  that  the  Liquid  Pepsin  had  digestive  power,  that  is, 
that  it  contains  Pepsin,  I  undertook  to  examine  some  of  the  Pep- 
sins and  preparations  of  Pepsin  usually  found  in  our  market,  in 
order  to  compare  their  solvent  power  upon  albumen  with  that  of 
my  own  preparation.  In  order  to  control  the  experiments,  and 
to  prevent  errors  from  the  difference  in  solubility  of  coagulated 
albumen  boiled  at  different  times,  I  accompanied  each  experi- 
ment with  a  proof  test.  This  consists  in  exposing  one  and  a 
half  drachms  of  coap-ulated  albumen  to  the  action  of  one  fluid- 
ounce  of  my  liquid  Pepsin  simultaneously  with  the  other  Pep- 
sins, subjecting  thereby  each  fluid  to  the  same  temperature, 
and  shaking  one  vial  as  often  as  the  other  one,  until  the  albu- 
men in  my  Pepsin  was  dissolved.  This  period  I  shall  call  the 
end  of  the  process." 
Wine  of  Pepsin,  prepared  from  the  mucous  membrane  of  the 
pig's  stomach  with  sherry  wine,  was  first  tested.  One  drachm  of 
coagulated  albumen  was  subjected  to  the  action  of  one  fluid- 
ounce  of  Wine  of  Pepsin. 
The  albumen  did  not  dissolve,  seemed  on  the  contrary  to  get 
more  compact,  and  the  wine  kept  clear,  while  by  all  other  ex- 
periments, where  solution  of  albumen  takes  place,  the  fluid  be- 
comes turbid. 
At  the  end  of  the  process  the  albumen  was  taken  out  of  the  ■ 
wine,  washed  with  water,  dried  on  filtering  paper  and  then 
weighed.    The  one  drachm  had  lost  only  fifteen  grains,  which  , 
loss  I  do  not  consider  as  having  been  dissolved,  as  the  albumen  . 
was  firmer  than  before  it  was  put  into  the  wine,  and  felt  like  soft 
india-rubber  between  the  fingers.    I  am  confident  that  the  loss 
is  owing  to  water,  which  the  albumen  lost  by  the  process.  To 
determine  whether  the  alcoholic  strength  of  the  Wine  of  Pepsin 
prevents  the  solution  of  albumen,  the  foregoing  experiment  was^ 
repeated,  with  the  difference  that  one  fluid-ounce  of  the  wine  was 
diluted  with  its  volume  of  distilled  water,  but  the  result  was  pre- 
cisely the  same. 
The  same  result  was  obtained  with  another  portion  of  my  own 
Wine  of  Pepsin,  with  Wine  of  Pepsin  prepared  by  a  -friend,  with 
Wyeth's  Wine  of  Pepsin  and  with  Wyeth's  Elixir  of  Pepsin. 
A  fresh  portion  of  mucous  membrane  was  now  extracted  :witk 
I 
