724         Standardisation  of  Digitalis  Preparations.  {ANo/emberPhia9ri™' 
Preparation 
Tested. 
Expt. 
"Number  of* 
Drops  Perfused 
Calculated  per 
100  Gm.  Frog. 
M.L.D.  from 
Graph. 
M.L.D. 
Colorimetric. 
M.L.D. 
by  In- 
jection. 
Tinct.  B  
I 
2 
3. 
1032  \ 
1031  J 
0.605 
0.6 
0.55  0.6 
Tinct.  10  
I  • 
2 
649) 
579  f 
0.5  to  0.55 
0-75 
much  depos- 
ited since  per- 
fusion expt. 
was  done. 
1  No 
|  data 
Standard  Tinct.  2.  .  . 
I 
2 
1063  ) 
1064  f 
0.615 
0.65 
0.6  to  0.65 
Tinct.  21.3. 18  
1 
2 
640) 
540  i 
0.43  to  0.48 
1 
0.4  to  0.5  0.4 
Tr.  from  Extract  Di- 
lution 1  in  10  .... 
1 
2 
1008 
726 
0.6 
0.51 
No  data 
No  data 
0.6 
0-45 
Tinct.  5  
56i 
0-45 
0.45  to  0.5 
No  data 
517 
0-43 
0.4  to  0.45 
No  data 
Standard    Tinct.  1, 
29-9-IO   
1231 
0.67 
0.6  to  0.75 
0.7 
tities  of  the  glucosides  present.  I  therefore  devised  the  following 
colorimetric  processes. 
These  are  partly  on  the  lines  of  Dr.  Martindale's  method,  but 
essential  differences  will  be  found  in  the  extraction,  precipitation, 
nitration,  and  also  in  the  "  working  up  "  of  the  resulting  glucosidal 
residues. 
Colorimetric  Process  A :  For  Water  Soluble  Glucosides. 
In  this  estimation  the  idea  is  to  obtain  the  water  soluble  gluco- 
sidal content  only,  and  to  eliminate  digitoxin  and  saponin.  Alcohol 
is  removed  from  the  tincture  to  be  tested  and  cold  water  solutions 
are  used  to  eliminate  as  much  digitoxin  as  possible,  this  glucoside 
being  almost  insoluble  in  cold  water.  Extraneous  matter  is  removed 
by  treatment  with  lead  acetate  solution,  nitration  being  effected 
through  kieselguhr  plates  in  Buchner  funnels.  Excess  of  lead  is 
removed  by  sodium  phosphate,  and  the  solution  again  filtered 
through  kieselguhr.  Precisely  the  same  conditions  must  be  observed 
in  each  estimation,  and  similar  amounts  of  kieselguhr  used. 
