Am.  Jour.  Phar in.  \ 
July.  1899.  J 
Bismuth  Subgallate. 
327 
properly  drying  the  precipitate,  a  soft  canary-yellow  product  was 
the  result.  It  compared  favorably  with  any  commercial  article,  and 
an  analysis  showed  it  to  contain  5  3*8 1  per  cent,  of  bismuth  oxide. 
Fifty  years  later,  B.  Fischer1  prepared  the  same  article  as  follows : 
Dissolve  1 5  parts  of  bismuth  nitrate  crystals  in  30  parts  of  glacial 
acetic  acid,  dilute  with  from  200  to  250  parts  of  water,  and  filter.  To 
this  filtrate  add,  with  constant  stirring,  a  warm  solution  of  5  parts 
of  gallic  acid  dissolved  in  from  200  to  250  parts  of  water.  The 
resulting  precipitate  is  allowed  to  subside,  the  supernatant  liquid 
decanted,  the  precipitate  transferred  to  a  strainer  and  washed  with 
water  until  the  wash-water  no  longer  gives  a  reaction  for  nitrates 
with  diphenylamine. 
It  is  quite  difficult  to  so  thoroughly  remove  the  nitrates  from  the 
bismuth  subgallate  by  washing  that  the  extremely  searching  rea- 
gent diphenylamine  will  no  longer  indicate  their  presence. 
In  1897  tvvo  patents  were  taken  out  on  bismuth  subgallate,  one 
in  France  and  the  other  in  the  United  States.  The  French  patent 
covers  a  process  for  its  manufacture,  and  intends  the  article  to  be 
used  as  a  pigment.  The  American  patent  covers  not  only  the  pro- 
cess of  manufacture,  but  the  chemical  product  itself,  even  to  the  per 
cent,  of  bismuth  it  contains,  and  intends  it  as  a  therapeutic  agent. 
The  French  patent,2  granted  to  "A  la  Compagnie  parisienne  de 
couleurs  d'aniline,"  reads  as  follows:  "48  kilogrammes  de  nitrate  de 
bismuth  neutre  sout  dissous  dans  de  l'acide  nitrique  delaye,  et  cette 
dissolution  est  additionnee  d'une  dissolution  de  19  kilogrammes 
d'acide  gallique  dans  40  litres  d'alcool  et  20  litres  d'eau.  Puis  on 
ajoute  de  l'alcali  caustique,  de  l'alcali  carbonique  on  des  corps  simi- 
laires  jusqu'a  ce  que  le  reaction  ne  soit  plus  que  facilement  acide; 
aussi  l'addition  d'acetate  de  soude,  meme  l'addition  d'eau,  provoque 
la  precipitation. 
!<  Le  precipite  obtainu  est  du  gallate  du  bismuth  basique  et  a  la 
formule 
Br/(OH)2 
"  La  theorie  demande  50*4  p.  100  de  (Bi),  nous  avous  trouve  49  4 
p.  100  de  (Bi).  II  se  presente  sous  forme  d'une  poudre  jaune, 
insoluble  dans  l'eau  et  dans  des  acides  delayes. 
1 1891,  Pharm.  Ztg.y  p.  400  ;  Abstr.  in  Amer.  Jour.  Pharm.,  63,  408. 
2 1 891,  Apr.  11,  Brevet  No.  212,712,  Vol.  78,  Part  II,  p.  44. 
