214  Digestive  Poiver  of  Certain  Pepsins  {^^£y\\m^' 
of  the  gentlemen  whose  preparations  I  tested,  my  sole  aim  being  to 
ascertain  their  medical  virtue. 
While  Dr.  Hawley  seemed  not  to  be  disposed  to  test  the  saccharated 
pepsin,  I,  on  the  contrary,  was  anxious  to  repeat  my  tests  in  reference 
to  his  preparation,  feeling  conscientiously  bound  to  d^  justice  to  him, 
in  case  I  had  erred  in  my  first  experiment. 
Some  time  ago  Mr.  Jacob  Dunton,  of  Philadelphia,  sent  me  a 
sample  of  Hawley's  and  Boudault's  Pepsins,  requesting  me  to  test 
them  with  mine,  at  the  same  tiuie  assuring  me  that  he  had  them  from 
a  reliable  source.  I  was  astonished  about  the  external  appearance  of 
Hawley's  pepsin,  as  it  was  entirely  different  from  the  one  I  had  tested 
before  and  bought  from  a  wholesale  house  here.  The  sample  was  a, 
quite  white  powder,  while  the  one  I  had  tested  before  was  of  a  yel- 
lowish color. 
The  tests  vv^ere  all  made  in  my  usual  way,  by  acidulating  one  fluid- 
ounce  of  water  with  ten  drops  of  hydrochloric  acid  and  adding  a 
certain  quantity  of  pepsin,  as  also  of  coagulated  albumen.  Eight 
grains  saccharated  pepsin,  100  grs.  albumen  ;  10  grs.  Hawley's  pepsin, 
90  grs.  albumen  ;  10  grs.  Boudault's,  90  grs.  albumen. 
After  three  and  one-half  hours'  digestion  at  105°,  the  saccharated 
pepsin  had  dissolved  the  albumen  entirely,  and  1  added  20  grains 
albumen  more,  and  continued  digestion  until  six  hours  had  elapsed. 
By  this  time  the  8  grains  saccharated  pepsin  had  nearly  dissolved  120 
grains  albuuien,  only  a  small  quantity  left  remaining.  In  Hawley's 
pepsin  about  double  the  quantity  of  albumen  was  undissolved  as  in 
the  saccharated  pepsin,  and  in  Boudault's  about  four  times  the 
quantity. 
At  the  same  time  with  the  foregoing  experiments,  1  had  tested 
another  article  of  Hawley's  pepsin,  which  I  had  procured  from  a  firm 
in  the  city,  of  whom  I  had  not  previously  bought.  In  appearance  it 
w^as  exactly  the  same  as  that  tested  before  and  mentioned  in  my  last 
paper,  and  the  result  proved  also  that  it  was  the  same  article,  as  10 
grains  did  not  fully  dissolve  15  grains  of  albumen  in  six  hours ;  and 
30  grains  left  of  60  grains  of  albumen  a  large  quantity  undissolved. 
Upon  communicating  these  results  to  Mr.  Dunton,  he  related  to 
me,  in  answer,  an  experiment  of  his,  by  which  10  grains  of  Boudault's 
and  8  grains  saccharated  pepsin  had  each  dissolved  90  grains  of  coa- 
gulated albumen  at  120°  in  six  hours,  while  Hawley's  (10  grains  to 
90  grains  albumen)  had  not,  and,  to  ntention  Mr.  Dunton's  own  words,. 
