326 
Bismuth  Subgallate. 
Am.  Jour.  Pharm , 
July,  1899. 
The  assays  in  which  one-half  hour  and  one  hour  maceration  was 
allowed  are  marked  in  the  table  a  and  b  respectively;  the  statement 
made  that  the  mixture  of  alcohol  and  ammonia  is  a  superior  solvent 
is  confirmed  by  the  slight  differences  noted  in  these  duplicate  assays. 
BISMUTH   SUBGALLATE;   ITS   HISTORY,  CHEMICAL 
COMPOSITION  AND  PROPERTIES. 
By  Lyman  F.  Keener.  * 
Research  Committee  B,  Pharmacopoeia  Revision. 
There  are  probably  few  chemicals  around  which  there  clusters  so 
much  that  is  interesting  as  bismuth  subgallate.  The  interest  mani- 
fests itself  in  the  history  of  its  preparation,  its  chemical  composition 
and  chemical  properties,  the  role  it  has  played  in  our  patent  laws, 
and  its  value  as  a  therapeutic  agent. 
In  1 84 1,  H.  Bley1  prepared,  described,  analyzed  and  assigned  a 
chemical  formula  to  this  compound.  In  order  that  there  may  not 
be  any  misunderstanding,  those  portions  of  the  original  communi- 
cations or  patents  which  are  of  especial  interest  will  be  reproduced 
in  this  paper.  "  Urn  gallussaures  Wismuthoxid  darzustellen,  wurde 
eine  Losung  von  basisch — essigsaurem  Wismuthoxid  in  vieler 
uberschiissiger  Essigsaiire  nebst  Salpetersaure  mit  einer  warmer 
Lbsung  von  Gallussaure  im  Ueberschuss  versetzt,  wodurch  sich  ein 
hellgelber  Niederschlag  erzeugte."  On  analysis  he  found  the  pre- 
cipitate to  contain  51*48  per  cent,  of  bismuth  oxide  and  assigned  to 
it  the  following  formula:  2BiO  -f  G  -f  2  aq. 
The  directions  of  Bley  for  preparing  bismuth  subgallate  are  not 
given  in  detail,  yet  the  following  method,  based  on  his  outlines,  gave 
the  writer  a  very  good  article.  To  300  grammes  of  bismuth  sub- 
nitrate,  in  a  container,  add  100  grammes  of  nitric  acid  (sp.  gr.  1-38) 
and  350  grammes  of  80  per  cent,  acetic  acid,  agitate  and,  when  solu- 
tion is  effected,  dilute  with  8  litres  of  distilled  water;  mix  well  and 
add,  while  stirring,  200  grammes  of  gallic  acid,  previously  dissolved 
in  8  litres  of  luke-warm,  distilled  water.  Wash  the  resulting  precipi- 
tate with  distilled  water  by  means  of  decantation,  until  the  wash- 
water  only  slightly  affects  blue  litmus  paper.    On  draining  and 
1  1841,  Arch,  der  Pharm.,  26,  169;  Abstr.  L,.  Gmelin's  Hand-book  of  Chem- 
istry, 1859,  Vo1-  I2>  P-  409. 
