'  }    Hydrargyrum  Iodidum  Rubrum ,  etc.  115 
• 
Cubic  centimetres 
ofdecinormal  solu- 
tion of  NH4  found 
in  fl.  gi  of  Dil. 
Phos.  Acid. 
Amount  of  NH4in 
fl.      of  Dil.  Phos. 
Acid. 
*%>  >P  tj 
■s-s  < 
Percentage  of  H3 
P04  combined 
with  NHr 
sfS  • 
2  s  « 
0 
Percentage  of  (N 
H4),HP04  in  Dil. 
Phos.  Acid. 
1 
1  1 
No.  1 
0.70 
.0194  grs. 
.0529  grs. 
.0926 
.0711  grs. 
.0147 
No.  2 
0.20 
.0055  " 
.0149  44 
.0261 
.0201  " 
.0042 
No.  3 
i-55 
0430  " 
.1170  " 
.2056 
.1576  « 
.0327 
No.  4 
°'35 
.0097  " 
.0264  " 
.0463 
.0355  " 
.0073 
No.  3  yielded  a  much  larger  amount  of  ammonium  than  any  of  the 
others,  which  is  accounted  for  by  the  fact  of  its  having  been  prepared 
at  a  comparatively  low  temperature. 
A  moderate  heat  was  employed  in  the  preparation  of  No.  1,  which, 
therefore,  gave  a  smaller  amount,  while  in  the  case  of  Nos.  2  and  4, 
the  boiling  temperature  was  applied,  consequently  a  much  smaller  yield 
was  obtained. 
It  is  evident  that  these  results  are  entirely  too  insignificant  to  be  of 
any  practical  importance,  yet,  after  all,  as  has  been  frequently  stated  by 
others,  it  is  difficult  to  improve  on  the  first  process  offered  by  the  U.  S. 
Pharmacopoeia,  against  which  the  principal  objection  offered  is  the  re- 
quisition of  constant  attention  to  prevent  explosion  or  breakage  j  this, 
however,  is  not  substantiated  by  the  experience,  either  of  myself  or 
those  of  whom  inquiry  has  been  made. 
HYDRARGYRUM   IODIDUM   RUBRUM   AND   OXIDUM  FLAVUM. 
BY  CHARLES  L.  MITCHELL. 
[Read  at  the  Pharmaceutical  Meeting,  February  i$th.) 
The  disadvantages  arising  from  the  use  of  mercuric  chloride  in  the 
preparation  of  the  above-named  mercurials  have  long  been  known 
to  pharmaceutists.  Owing  to  its  comparative  insolubility  in  water,  a 
large  bulk  of  liquid  is  required  in  order  to  obtain  any  appreciable  quan- 
tity of  product,  thus  necessitating  the  use  of  large  vessels  when  manu- 
facturing in  any  quantity.  Heat  is  also  required,  in  order  that  the 
water  shall  take  up  as  much  of  the  mercuric  chloride  as  possible,  and 
thus  lessen  the  disadvantage  of  bulky  utensils.  This,  however,  only 
partially  removes  the  difficulty,  and  runs  the  additional  risk  of  breakage 
of  vessels,  etc.  It  seems,  therefore,  that  the  corrosive  sublimate  used 
in  the    officinal  processes    for   making  the  red  iodide  and  yellow 
