274  Bismuth  Oxyiodide.  {Amjl™J;imaTm' 
As  a  final  attempt,  bismuthous  hydrate  was  precipitated,  and  this 
treated  with  hydriodic  acid ;  the  product  was  amorphous  and  of  a  red 
color.  After  a  number  of  trials  the  following  formula  was  adopted 
as  giving  a  satisfactory  preparation  : 
Iodine  4.6  gm. 
Bismuth  subnitrate  10  gm. 
Mtric  acid,  1*42  ...10  cc. 
Solution  of  soda,  U.  S.  P  150  cc. 
Water,  a  sufficient  quantity. 
The  iodine  is  covered  with  50  cc.  water,  and  converted  into  hydrio- 
dic acid  by  passing  H2S  through  the  mixture,  boiling  to  remove  excess 
of  H2S  and  filtering. 
The  subnitrate  is  dissolved  in  the  nitric  acid,  diluted  with  10  cc. 
water,  and  then  enough  water  added  to  produce  a  slight  permanent 
opalescence ;  this  mixture  is  then  slowly  poured  into  the  solution  of 
soda,  taking  the  precaution  to  stir  constantly.  The  precipitate  is 
washed  by  decantation  until  the  washings  cease  to  blue  red  litmus 
paper;  50  cc.  water  added  to  it,  and  the  hydriodic  acid  gradually 
poured  in  until  after  stirring  and  allowing  to  settle  the  supernatant 
liquid  has  a  yellow  color.  The  oxyiodide  is  washed  by  decantation, 
removed  to  a  filter,  allowed  to  drain,  and,  finally,  dried  at  a  temper- 
ature not  exceeding  100°  C.  The  oxyiodide  so  gotten  has  a  light  yel- 
lowish-red color,  and  contains  no  water  of  crystallization,  as  was  found 
by  analyzing  some  made  without  the  application  of  heat. 
The  process  is  tedious  and  laborious ;  the  variability  of  the  com- 
mercial subnitrate  tends  to  make  it  wasteful.  Ordinarily  the  subni- 
trate yields  from  79  to  82  per  cent,  of  oxide,  but  in  the  above  experi- 
ments the  salt  gave  as  much  as  85  per  cent.  Bi203.  It  was  found  that 
in  the  manufacture  of  this  ammonium  hydrate  had  been  used  to  increase 
the  yield  as  the  odor  of  ammonia  was  perceptible  on  warming  with  INa 
OH. 
The  amount  of  iodine  given  above  was  calculated  to  convert  10  gm. 
of  this  subnitrate  into  oxyiodide,  and  any  one  making  large  quantities 
would  do  well  to  examine  the  subnitrate  for  its  percentage  of  oxide 
and  make  a  calculation  to  suit. 
Lrinseed  oil  has  been  found  by  a  correspondent  of  the  Boston  Med.  and 
Surg.  Jour,  to  be  a  very  efficient  remedy  in  pruritus  ani  with  no  rectal  com- 
plications; when  freely  used  externally  it  gives  immediate  relief. 
