Am.  Jour.  Pharm. 
May,  1907. 
The  Gambir  of  Commerce. 
203 
he  knew  to  be  free  from  arsenic.  This,  when  placed  in  his  apparatus, 
gave  the 'black  stain  on  the  porcelain,  which  stain  he  had  supposed 
to  be  arsenic. 
On  looking  into  the  matter  further  1  found  that  while  silver 
arsenate  is  readily  dissolved  by  ammonia,  the  red-brown  stain  gotten 
as  above  described,  did  not  dissolve  ;  that  bismuth  pentoxide,  gotten 
by  heating  the  so-called  bismuthic  acid  (which  could  be  obtained  by 
oxidizing  bismuth  nitrate),  is  described  as  a  brown  powder ;  that 
the  black  stain  when  dissolved  in  concentrated  nitric  acid  and 
evaporated  down  with  hydrochloric  acid,  gave  with  hydrogen  sul- 
phide a  black  precipitate,  whereas  arsenic  yields  under  like  treat- 
ment a  yellow  sulphide. 
The  stain  was  thus  conclusively  shown  to  be  bismuth  and  not 
arsenic. 
I  have  written  the  above  to  impress  the  importance  of  something 
(if  nothing  more  than  a  cotton  wad)  to  arrest  the  particles  from  the 
generator,  in  testing  for  arsenic  in  bismuth  preparations,  and  because 
I  have  been  told  by  this  druggist  (who  is  more  skilled,  I  believe,  in 
chemical  matters  than  the  majority)  that  ninety-nine  out  of  a  hun- 
dred would  carry  out  the  test  as  he  did — and  so  be  led  to  a  wrong 
conclusion  ;  and  because  we  were  shown  that  bismuth  will,  under 
the  conditions  mentioned,  form  a  stain  like  arsenic  or  antimony, 
which  stain  I  have  never  seen  mentioned,  although  the  fact  of  its 
formation  may  be  well  known. 
Of  course  I  did  not  make  any  attempt  to  show  what  caused  the 
suspicious  symptoms  in  the  patient ;  I  was  only  concerned  with  the 
fact  that  they  were  not  caused  by  arsenic  in  the  bismuth  preparation. 
Tulane  University  of  Louisiana, 
New  Orleans,  La. 
THE  GAMBIR  OF  COMMERCE. 
By  Charges  H.  LaWau,. 
The  replacing  of  catechu  of  the  1890  Pharmacopoeia  by  gambir 
in  the  U.S.P.,  8th  Rev.,  was  commented  upon  favorably  by  prac- 
tically every  critic  of  the  book  when  it  made  its  first  appearance. 
Some  time  afterward  dissatisfaction  was  expressed  by  certain  persons 
