Oxides  in  Mercurial  Preparations.  47 
THE  PRESENCE  OF  OXIDES  OF  MKRCURY  IN  BLUE 
PILL  AND  IN  OTHER  MERCURIAL  PREPARA- 
TIONS.^ 
By  HAROI.D  Senier,  F.I.C.,  F.C.S. 
My  attention  has  just  been  called  to  a  paper  by  Messrs.  Dechau  and 
Maben  on  "  The  Strength  and  Condition  of  Commercial  Specimens 
of  Hydrargyrum  cum  Creta,  Pilula  Hydrargyri  and  Unguentum 
Hydrargyri/'^  read  at  the  Hastings  meeting  of  the  British  Pharma- 
ceutical Conference.  This  paper  is  an  attempt  to  further  elucidate  the 
question  of  the  existence  or  non-existence  of  oxides  of  mercury  in  these 
preparations,  and  gives  the  results  of  the  examination  of  some  com- 
mercial samples  of  each  of  them,  including  an  estimation  of  the  metallic 
mercury  and  the  two  oxides.  The  results  obtained  by  Messrs.  Dechan 
and  Maben  may  be  summarized  as  follows :  In  hydrargyrum  cum 
creta  they  find  a  considerable  proportion  of  oxides  of  mercury,  in  one 
sample  as  much  as  6*15  per  cent,  of  mercurous  oxide  and  2*8  per  cent, 
of  mercuric  oxide.  In  pilula  hydrargyri,  out  of  eight  samples  ex- 
amined, in  six  they  failed  to  find  any  trace  of  oxides,  although  one 
mass  was  four  years  old.  In  unguentum  hydrargyri,  out  of  twelve 
samples  examined,  in  two  only  was  oxide  found,  and  in  these  only  a 
very  small  percentage.  These  results  are  so  materially  opposed  to 
those  obtained  by  myself  in  an  investigation  of  the  same  subject  as  to 
indicate  an  error  on  the  part  of  one  of  us,  either  in  method  or  experi- 
ment. This  is  particularly  the  case  in  regard  to  pilula  hydrargyri, 
the  results  of  my  examination  of  which  I  recorded  in  a  communica- 
tion to  the  Pharmaceutical  Society  in  February,  1876.^ 
The  method  adopted  by  Messrs.  Dechan  and  Maben  for  the  estima- 
tion of  the  oxides  of  mercury  is  to  digest  the  substance  under  examina- 
tion in  hot  or  boiling  acetic  acid,  and  after  washing  the  residue  with 
the  same  menstruum  to  treat  the  acid  solution,  supposed  to  contain  the 
two  oxides  as  acetates,  first  with  hydrochloric  acid  to  precipitate  mer- 
curous chloride,  and  then  with  sulphuretted  hydrogen  to  precipitate 
'  Read  at  an  Evening  Meeting  of  the  Pharmaceutical  Society  of  Great 
Britain,  Wednesday,  November  5,  1884. 
"Phar.  Jour.,"  Series  iii.  No.  743,  p.  230;  "Am.  Jour.  Phar.,"  1884,  p. 
554. 
^  "  Phar.  Jour.,"  Series  iii.  No.  293,  p.  621 ;  "  Am.  Jour.  Phar.,"  1876,  p. 
143. 
