232 
Unguentum  Hydrargyri  Nitratm. 
(  Am.  Jour.  Pharm. 
1      May,  1883. 
evaporated  over  a  sand-bath,  the  residue  from  the  tincture  made  with 
absolute  alcohol  weighing  0*1  gm.,  and  from  the  other  0*15  gm.  Each 
residue  was  dissolved  in  distilled  water,  and  the  solutions  were  treated 
with  chlorine  gas ;  in  neither  solution  could  iodine  be  detected  by 
starch  or  carbon  bisulphide.  Both  residues,  amounting  to  1*0  and  1'5 
per  cent.,  respectively,  consist  mainly  of  chloride  of  sodium ;  their 
solutions  in  distilled  water,  on  being  tested  Avith  nitrate  of  silver, 
yielded  a  copious  precipitate,  which  was  soluble  in  ammonia. 
On  evaporating  5  gm.  of  the  tincture  made  with  absolute  alcohol 
alone,  merely  a  trace  of  residue  was  obtained. 
It  seems  as  if  the  addition  of  salt  in  the  preparation  of  this  tincture 
aids  the  solution  of  the  iodine  only  mechanically,  and  that  a  compound 
of  sodium  and  iodine  is  not  formed. 
NOTE  ON  UNGUENTUM  HYDKARGYRI  NITRATIS. 
By  Henry  C.  C.  Maisch. 
Head  at  the  Pharmaceutical  Meeting^  Apr-il  11th. 
The  ointment  was  prepared  according  to  the  formula  published  in 
the  '^American  Journal  of  Pharmacy,'^  March,  1883,  page  145.  The 
lard  and  neat's  foot  oil  were  heated  together  until  the  thermometer 
registered  between  150°  and  160°  F.,  when  the  lamp  was  removed, 
but  the  temperature  continued  to  rise  until  the  mercury  stood  betw^een 
190°  and  200°  F.  When  the  mixed  fats  had  cooled  down  to  170°  the 
camphor  was  dissolved  therein,  and  soon  after  the  mercury  previously 
dissolved  in  the  nitric  acid  was  added,  no  effervescence  being  observed. 
The  mixture  was  then  stirred  with  a  horn  spatula  while  cooling, 
yielding  an  ointment  of  a  yellow  color,  which  in  two  days  darkened 
considerably,  even  without  bringing  it  in  contact  with  an  iron  spatula. 
A  portion  of  this  ointment  was  stirred  with  an  iron  spatula  when  it 
became  rapidly  dark  colored. 
To  be  certain  whether  or  not  the  previous  heating  of  the  fats  had 
any  effect  on  the  ointment,  another  quantity  of  the  ointment  was 
made,  the  melted  fats  being  kept  in  a  waterbath  at  a  temperature  not 
exceeding  170°  F.  After  the  addition  of  the  camphor,  followed  by 
that  of  the  solution  of  mercury  in  the  nitric  acid,  a  slight  effervescence 
was  observed.  A  portion  of  this  ointment,  worked  with  an  iron 
spatula,  was  affected  in  a  similar  manner  as  in  the  preceding  experi- 
ment, while  that  portion  in  the  preparation  of  which  a  horn  spatula 
was  used,  retained  its  yellow  color. 
