ON  HYDRARGYRI  IODIDUM. 
203 
and  the  whole  beaten  until  about  one-half  is  evaporated.  If  the 
oil  is  pure,  a  brownish  yellow  solution  without  any  crystalline 
deposit  will  be  obtained  ;  if  it  contains  nitrobenzole,  a  larger  or 
smaller  quantity  of  a  hard  brown  crystalline  mass  will  precipi- 
tate in  the  colorless  supernatant  liquid. 
I  will  only  add  that  in  preparing  nitrobenzole,  it  often  occurs, 
after  mixing  the  raw  benzole  with  the  acids,  that  the  product  as- 
sumes a  dark  brown  color,  and  the  manufacturer,  to  make  it 
saleable,  throws  the  whole  with  a  proportionate  quantity  of 
water  into  a  still  and  distils  it  over. 
The  remainder  contains  like  the  wash-waters  a  pretty  large 
quantity  of  picric  acid. 
ON  HYDRARGYRI  IODIDUM. 
By  Roland  Seeger,  of  Philadelphia. 
In  the  lately  published  Proceedings  of  the  American  Pharm- 
aceutical Association,  among  other  papers  of  great  interest  by 
Dr.  E.  R.  Squibb,  one  concerning  the  article  which  forms  the 
subject  of  this  essay  attracted  my  attention.  I  was  the  more 
interested  in  this  subject  from  thr»  fact,  that  the  conclusion 
which  the  high  authority  arrived  at — to  wit — the  abandonment 
of  the  preparation,  was  certainly  to  be  regretted,  as  the  practi- 
tioner has  found  it  a  valuable  remedy  in  combatting  disease. 
I  find  the  first  mention  of  this  protosalt  of  mercury  in  M. 
Henry's  paper,  which  appeared  in  the  August  number  of  the 
"  Journal  de  Pharmacie  "  for  1828,  translated  to  the  pages  of 
our  own  Journal  for  October,  1829  page  204.  This,  the  origi- 
nal process,  was  the  double  decomposition  of  the  proto-nitrate 
of  mercury  by  a  solution  of  iodide  of  potassium. 
This  plan  was  objectionable  in  consequence  of  the  difficulty 
attendant  upon  the  preparation  of  a  pure  mercurous  nitrate; 
and  I  find  on  page  353  of  the  third  volume  of  our  Journal, 
translated  from  the  "Journal  de  Pharmacie"  for  August,  1831, 
a  memoir  by  M.  Berthemot,  reviewing  the  labors  of  M.  Henry  on 
this  subject.  So  unsatisfactory  were  the  results  of  his  experi- 
ments, that  he  recommended  the  process  of  triturating  the 
