Am.  Jour.  Pharm. 
May.  1908. 
Bismuth  Subgallate. 
209 
macopceial  tests  are  included,  all  of  which  demonstrate  that  our 
manufacturers  are  doing  their  utmost  in  complying  with  our  rigid 
requirements. 
It  will  be  noted  that  not  one  of  the  samples  strictly  fulfils  the 
requirements  of  test  for  the  "absence  of  free  gallic  acid"  as  given 
in  paragraph  5,  page  75  (U.S.P.).  In  order  to  ascertain  the  cause 
and  also  to  determine  the  quantity  of  free  gallic  acid  present,  5 
grammes  of  each  of  the  samples  was  thoroughly  agitated  with  30 
c.c.  of  ether,  filtered,  washed  with  two  further  portions  of  10  c.c.  each, 
and  the  filtrates,  after  distilling  off  the  ether,  were  dried  over  sul- 
phuric acid  and  weighed.  The  residues,  which  varied  from  002  to 
O  08  per  cent.,  consisted  of  fatty  matter  with  but  traces  only  of  free 
gallic  acid,  the  former  originating  evidently  from  the  gallic  acid  used. 
Since  this  residue  is  present  in  very  small  quantities,  with  but  traces 
of  gallic  acid,  the  test  would  be  more  reasonable  and  just,  if  applied 
in  this  manner,  than  by  employing  the  supersensitive  litmus.  The 
following  test  is  suggested  in  lieu  of  our  present  one,  being  less 
strenuous  and  conformed  to  by  all  of  our  manufacturers :  "If  I  gramme 
of  the  salt  be  well  shaken  with  10  c.c.  of  ether  and  filtered  through 
a  double  filter,  wetted  with  ether,  the  filtrate  evaporated  to  dryness 
should  not  leave  a  weighable  residue,  nor  should  an  immediate  blue- 
black  coloration  appear  after  the  addition  of  2  drops  of  ferric  chloride 
Weight  Volume. — There  being  some  difference  in  the  comparative 
lightness  (bulk)  of  the  various  samples,  a  simple  expedient  was 
adopted,  whereby  the  weight  volume  could  be  approximately  meas- 
ured, i-o  gramme  of  the  sample  was  introduced  into  a  narrow 
graduated  cylinder,  and  then  shaken  down  by  tapping  until  its  vol- 
ume ceased  to  decrease ;  the  volume  was  then  noted. 
The  samples  examined  were  taken  from  original  sealed  containers, 
BISMUTH  SUBGALLATE. 
T.  S: 
U.  S.  P. 
Free  G.  A. 
Sample.    Bi.2Oy    Nitrates.  Test. 
Proposed 
G.  A.  Residue 
Test. 
Ether  Ex- 
tract. 
Per  Cent. 
Color. 
Wt.  Vol. 
1.  52*6  o  Positive. 
2.  53-6  0 
None. 
Bright  yellow. 
Light  brown. 
Yellow. 
"4 
3-  53'5 
4-  55'5 
5-  53'° 
0*02 
0*03 
0-025 
0*02 
Bright  yellow. 
6.         53"  3  o 
Yellow. 
