534 
Valuation  of  Drugs  and  Foods. 
Am.  Jour.  Pharm 
November,  1899. 
Drug. 
Number  of  C.c.  of  Water  Required  to 
Produce  a  L,ight  Straw-colored  So- 
lution with  "ioo  Gramme  of  Drug 
+  20  C.c.  of  KOH  Solution. 
Dose  in  Grammes. 
Senna  (  Alexandria)    .  . 
35  c.c. 
4-8  grammes. 
Senna  (Tinnivelly)     .  . 
35  c.c. 
4-8 
Rheum  
95  c.c. 
0-6-2  " 
115  c.c. 
1-2  " 
Rhamuus  Purshiana  .  . 
115  c.c. 
0*6-4  " 
295  c.c. 
O'2O-0'6o  " 
395  c.c. 
•03-T2  * 
The  shade  of  color  is  not  pure  yellow,  but  varies  in  the  different 
drugs.  With  the  sennas,  the  color  is  nearly  pure  yellow.  The 
solutions  of  aloin  and  aloes  are  somewhat  yellowish-green.  Those 
of  rheum  and  cascara  sagrada  are  yellowish-purple.  The  solutions 
of  frangula  are  still  more  purple. 
It  should  be  noted  that,  in  comparing  the  above  solutions  with  a 
solution  of  chrysophanic  acid,  the  following  proportions  give  a 
solution  of  about  the  same  intensity  as  the  drugs  examined.  To 
•025  gramme  of  chrysophanic  acid  add  10  c  c.  ?  KOH  solution  -f- 
15  c.c.  water.  To  this  solution  240  c.c.  of  water  are  added,  when 
there  results  a  light  straw-colored  liquid,  resembling  that  of  fran- 
gula rather  closely. 
It  ought  to  be  said,  in  presenting  these  results,  that  the  idea  has 
not  been  to  carry  the  comparisons  outside  of  the  same  class  of  drugs. 
It  would  appear,  however,  that  it  is  possible  to  go  even  further,  as  we 
see  in  the  above  table  that  there  is  a  direct  ratio  between  the  doses 
of  the  drugs  and  their  colorimetric  valuation;  or  we  may  say  that 
the  larger  the  dose  required,  the  less  the  proportion  of  water 
necessary  to  produce  a  solution  of  equal  intensity  to  other  drugs  of 
its  class  and  vice  versa. 
(C)  In  working  with  certain  other  drugs  that  contain  coloring  prin- 
ciples, we  find  that  fairly  accurate  values  may  be  obtained  on  compar- 
ing commercial  specimens  with  material  whose  value,  by  reason  of 
experiment  or  experience,  we  know  something  about.    If  we  take, 
