^"'sSt.!im''°'"}    Relative  Value  of  Different  Pepsin  Tests. 
473 
To  further  illustrate  the  test,  I  append  the  following  results  obtained 
with  commercial  pepsins  : 
Peptone  formed  from  0-1  gm. 
pepsin  in  3  hours. 
Pepsin  G  0-5844 
E  0-4972 
"       B  0-4722 
"       F,  crystal  0-4682 
C  (saccharated)  0.4676 
H  0-4598 
A  (saccharated?)  0-4370 
A  (saccharated)  0-4246 
D  plain,  soluble  0  3470 
D  pure,  scales  0*3250 
"       D  pure,  another  sample  0-3146 
"       I  (saccharated)  0-2780 
J  French  0-1848 
K  (saccharated)  0-1738 
These  tests  were  all  made  with  the  same  quantity  of  pepsin,  whether 
the  latter  was  saccharated  or  not,  and  I  think  are  a  fair  indication  of 
the  relative  values  of  the  different  pepsins. 
It  may  be  objected  that  this  test  does  not  do  a  concentrated  pepsin 
full  justice,  on  the  ground  that  the  latter  would  form  a  much  greater 
proportion  of  peptone  and  thus  retard  if  not  completely  arrest  any 
further  action  of  the  pepsin  upon  the  albuminoid  matter. 
In  order  to  test  this  question,  I  saccharated  samples  of  E,  F  and 
H  respectively,  according  to  Manwaring^s  directions,  which  is  equiva- 
lent to  diluting  with  mere  accidulated  water,  and  submitted  them  to 
the  same  conditions  as  before  and  obtained  the  following  results  : 
Peptone  formed  from  0"1  gm. 
pepsin  in  3  hours. 
Pepsin  E  0  2620 
"      F  0-1240 
"      H  0-1250 
It  will  be  observed  that  in  these  tests  the  figures  are  considerably 
lower  than  in  the  former  ones  ;  but  it  must  be  remembered  that  the 
pepsins  with  which  the  tests  were  made  were  twenty  times  weaker,  or 
rather  more  diluted,  than  in  the  previous  tests,  and  notwithstanding 
this  the  peptone  formed  is  proportionally  larger  than  before.  This 
would  clearly  show  that  the  dilution  is  beneficial  in  the  case  of  con- 
centrated pepsins,  as  it  corrects  the  retarding  action  of  peptone.  As 
the  dilution  in  these  last  tests  was  twenty  times  greater  than  in  the 
