A%p°rnr;if9h7arm'}    Note  on  Ointment  of  Mercuric  Nitrate.  209 
tion  of  the  thoroughly  washed  substance  with  chlorine-free  calcium 
carbonate  on  platinum  foil.  The  mass  was  allowed  to  cool,  then 
dissolved  in  water  by  the  aid  of  nitric  acid,  and  silver  nitrate,  T.  S., 
added.  This  reagent  produced  a  white,  curdy  precipitate  of  silver 
chloride  insoluble  in  nitric  acid. 
To  estimate  the  chlorine  quantitatively,  -0813  gramme  of  the 
chlorine  derivative  was  intimately  mixed  with  chlorine-free  calcium 
carbonate,  and  heated  in  a  glass  tube,  closed  at  one  end,  until  the 
carbon  was  completely  burned  off.  The  tube  was  then  broken,  and 
it  and  the  contents  were  introduced  into  a  beaker.  Water  was 
added,  and  the  whole  warmed  and  complete  solution  of  contents 
effected  by  the  aid  of  nitric  acid.  The  solution  was  filtered  clear, 
the  filter  carefully  washed,  adding  the  washings  to  the  filtrate,  and 
then  precipitated  with  silver  nitrate.  The  precipitate  was  collected, 
washed  with  hot  v/ater  and  dried  at  1300  C.  to  constant  weight. 
The  weight  of  silver  chloride  so  produced  was  -0425  gramme, 
which  corresponds  to  -0105  gramme  of  chlorine,  or  12-91  per  cent, 
of  the  weight  of  the  derivative  taken.  Assuming  that  one  hydro- 
gen atom  is  replaced  by  every  chlorine  atom  introduced,  the  for- 
mula of  the  derivative — admitting  the  formula  for  marrubiin  to  be 
C30H43O6 — would  be  C30H41Cl2O6,  the  theoretical  amount  of  chlorine 
in  which  is  12-47  per  cent. 
Marrubiin  dichloride  is  a  yellowish-white,  hard,  wax-like  sub- 
stance, soluble  in  ether  and  alcohol,  from  which  solvents,  however, 
it  could  not  be  obtained  in  crystalline  form,  even  after  repeated  at- 
tempts at  crystallization. 
When  heated  it  becomes  transparent  at  63 0  C. 
NOTE  ON  OINTMENT  OF  MERCURIC  NITRATE. 
By  Joseph  W.  England. 
Probably  no  official  ointment  has  been  more  carefully  studied 
than  has  the  familiar  citrine  ointment.  To  the  physician  its  medi- 
cinal action  is  peculiar  and  full  of  interest.  Through  its  free  nitric 
acid,  when  applied  to  an  epidermis  more  or  less  altered  by  patho- 
logical change,  it  rapidly  penetrates  the  superficial  tissue,  and 
sharply  stimulates  the  subdermal  tissue  to  absorb  the  soluble  mer- 
curic salt,  thus  inducing  a  local,  and  possibly,  to  some  extent,  a  con- 
stitutional alterative  action.     The  danger  of  salivation  from  a  too 
