Am.  Jour.  Pharm. 
June,  1897. 
Red  Mercuric  Oxide. 
3ir 
Sample. 
(1)  5  c.c.  gave  21*6  c.c.  NO. 
(2)  5  c.c.     "    21-6   "  " 
(1)  5  c.c.  "  50-0  " 
(2)  5  c.c.  "  50  0  " 
(1)  5  c.c.  "  47"o  " 
(2)  5  c.c,  "  47'2  " 
The  displacement  of  air  from  the  aqueous  solution  of  the  potas- 
sium iodide  might  also  be  overcome  by  boiling  the  solution  and 
allowing  it  to  cool  out  of  contact  with  air  just  previous  to  use,  but 
this  method  was  not  tried. 
The  quality  of  the  spirit  of  nitrous  ether  dispensed  is  remarkably 
poor. 
I  have  read  with  interest  Mr.  Charles  H.  La  Wall's  paper  on  the 
"  Consideration  of  Some  Recent  Suggestions  Concerning  Ointment 
of  Mercuric  Nitrate,"  as  published  in  the  current  issue  of  the  Ameri- 
can Journal  of  Pharmacy. 
It  will  be  recalled  that  I  urged  the  use  of  red  mercuric  oxide  in 
place  of  metallic  mercury,  in  the  making  of  citrine  ointment.  This 
practice  was  suggested  as  an  alternative,  and  not  as  a  substitute  for 
the  official  formula.  The  average  pharmacist  always  has  red  mer- 
curic oxide  in  stock ;  he  does  not  always  have  metallic  mercury, 
and  it  was  thought  to  be  directly  on  the  line  of  increased  convenience 
to  urge  the  substitution  of  the  oxide,  in  proportionately  larger 
quantity,  for  the  metal,  when  occasion  required. 
To  the  use  of  red  mercuric  oxide  in  place  of  metallic  mercury  for 
this  purpose,  Mr.  LaWall  says :  "  As  to  the  relative  purity  of  the 
two  substances,  the  experience  of  a  large  manufacturing  establish- 
ment shows  that  the  commercial  metallic  mercury  is  of  far  greater 
uniformity  and  purity  than  the  red  oxide  of  commerce." 
This  statement  does  not  accord  with  the  writer's  information.  A 
letter  from  one  of  the  leading  firms  of  manufacturing  chemists  says  : 
"  We  would  state  that  our  red  mercuric  oxide  conforms  strictly  to 
the  requirements  of  the  United  States  Pharmacopoeia,  and  we  regard 
it  as  equal  in  purity  to  metallic  mercury." 
NOTE  ON  RED  MERCURIC  OXIDE. 
By  Joskph  W.  Kngi^and. 
