NOTE  ON  ARSENIC  IN  TRINITRATE  OF  BISMUTH.  169 
allaying  the  cravings  of  the  intemperate.  I  have  no  doubt  that, 
if  it  be  fairly  tried,  practitioners  will  find  it  an  exceedingly 
useful  remedy.  It  may  be  given  in  doses  of  from  20  or  30  to 
60  minims  or  more,  in  a  glass  of  water,  two  or  three  times  a 
day." — Am.  Journ.  Med.  See.  Jan.  1860. 
NOTE  ON  ARSENIC  IN  TRINITRATE  OF  BISMUTH. 
By  Mr.  John  Morland,  Analytical  Chemist. 
During  the  progress  of  Dr.  Smethurst's  trial,  the  presence  of 
arsenic  in  commercial  trisnitrate  of  bismuth  was  brought  forward 
by  the  witnesses  for  the  prisoner  to  account  for  the  arsenic  found 
by  Dr.  Taylor  in  one  of  the  evacuations.  Wishing  to  repeat  the 
examination  of  trisnitrate  of  bismuth  for  arsenic,  I  obtained  two 
samples  of  it  from  Pharmaceutical  Chemists  in  the  City  ;  in  both 
I  found  traces,  though  but  slight  ones,  of  arsenic.  I  was,  how- 
ever, surprised  to  find  that  both  the  samples  contained  chlorine  ; 
in  one  it  corresponded  to  72.5  per  cent,  of  subchloride,  in  the 
other  to  19.2  per  cent.  As  the  subchloride  contains  a  larger  per- 
centage of  bismuth  than  the  subnitrate,  it  can  scarcely  be  econ- 
omical to  substitute  it  for  the  latter ;  probably  the  finer  powder 
obtained,  together  with  the  more  easy  solution  of  bismuth  in 
aqua  regia  than  in  nitric  acid,  is  the  inducement.  I  understand 
that  a  subcarbonate  is  also  prepared  in  London. 
The  above  fact  is  not  without  a  bearing  on  the  presence  of 
arsenic  in  the  bismuth  preparations,  as  arseniate  of  bismuth  is 
barely  soluble  in  nitric  acid,  whilst  in  hydrochloric  acid  it  is 
freely  dissolved,  and  reprecipitated  with  the  subchloride  on  the 
addition  of  water.  To  prove  this,  I  prepared  subnitrate  and 
subchloride  of  bismuth  from  metallic  bismuth,  to  which  a  large 
quantity  of  arsenious  acid  had  been  added ;  the  solutions,  as 
ordered  by  the  Pharmacopoeia,  were  both  filtered  before  per- 
cipitation  by  water,  and  resulting  subsalts  tested  for  arsenic ; 
there  was  only  a  trace  in  the  subnitrate,  whilst  in  the  subchloride 
it  was  abundant,  as  also  in  subcarbonate  prepared  from  the 
chloride. 
Mr.  John  Huskisson,  jun.,  observed  that,  considering  the 
way  in  which  subnitrate  of  bismuth  was  usually  prepared,  there 
could  not  be  more  than  a  mere  trace  of  arsenic  in  it.  The 
