^MSi^^mL  "}  Digestive  Power  of  Commercial  Pejpsins.  109 
it  a  place  in  your  Journal.  In  doing  this,  I  wish  it  to  be  understood 
that  no  unfavorable  reflections  are  intended  towards  Mr.  SchefFer. 
On  the  contrary,  his  article  bears  intrinsic  evidence  of  candor  and 
scientific  accuracy.  It  is  my  belief  that  he  unfortunately  procured  a 
damaged  sample  of  my  pepsin,  as  he  admits  he  did  of  Boudault's  on 
a  former  occasion. 
My  only  object  in  this  communication  is  to  set  myself  right  before 
the  professions  of  medicine  and  pharmacy. 
In  this  test  the  same  varieties  of  pepsin  are  used  and  the  same 
method  pursued  as  by  Mr.  Scheffer,  except  drying  the  residue,  which, 
has  been  done  to  secure  greater  accuracy  of  result. 
In  each  of  four  suitable  bottles  were  placed  sixty  grains  of  coagu- 
lated albumen  (white  of  egg),  one  fluidounce  of  water,  five  drops  of 
muriatic  acid,  and  five  grains  of  Boudault's,  Grimault's,  Houghton's, 
and  Hawley's  pepsin  respectively. 
These  were  kept  in  the  same  water-bath,  at  a  temperature  of  98°  to 
102°  Far.,  and  frequently  agitated  during  the  space  of  four  hours. 
At  the  end  of  this  time  the  undigested  portions  were  removed  and 
drained  of  moisture. 
The  following  appearances  were  presented  by  the  residua  respec- 
tively : 
That  digested  in  Houghton's  pepsin  appeared  unaltered  in  form^ 
color  and  quantity,  and  soon  became  dry  as  before  digestion. 
That  digested  in  Grimault's  had  lost  something  of  its  opacity,  the 
angles  were  rounded,  the  quantity  sensibly  diminished,  and  presented 
an  appearance  of  increased  softness  and  moisture. 
That  digested  in  Boudault's  possessed  a  slightly  translucent  appear- 
ance, the  angles  of  the  remaining  pieces  entirely  destroyed  and  the 
quantity  decidedly  diminished,  wet  and  inclined  to  remain  so. 
That  digested  in  Hawley's  pepsin  had  become  nearly  translucent 
and  amorphous,  the  quantity  much  more  diminished  than  the  last  and 
very  wet,  evidently  considerable  peptone  adhering  to  the  undigested 
portions. 
These  residua,  together  with  sixty  grains  of  coagulated  albumen, 
which  had  been  subjected  to  no  digestion,  were  placed  separately  upon 
clean  earthen  plates  and  dessicated  to  dryness. 
This  dessication  was  employed  to  avoid  the  difference  of  weight  due 
to  the  difi'erence  of  capacity  for  retaining  water  possessed  by  sub- 
stances in  different  stages  of  digestion. 
