TINCTURE  AND  FERRATED  TINCTURE  OF  BARK.  195 
rufo'cinchotanmc  acid,  which  is  in  accordance  with  the  nomen- 
clature adopted  for  the  red  bodies  obtained  hj  oxidation  from 
the  various  tannic  acids. 
Whether  the  precipitate  appearing  in  simple  tincture  of  bark 
consists  only  of  this  rufo-cinchotannic  acid  and  the  alkaloids,  I 
have  neglected  to  ascertain,  possibly  kinic  acid  may  be  likewise 
found  in  it.  To  this  my  attention  was  not  drawn,  until  I  ope- 
rated with  the  precipitates  from  ferrated  tincture  of  bark  ;  when 
they  were  treated  with  diluted  sulphuric  or  muriatic  acid,  and 
the  filtrate  subsequently  over-saturated  with  ammonia,  no  pre- 
cipitate of  oxide  of  iron  took  place,  but  sulphocyanide  of  potas- 
sium indicated  the  presence  of  a  considerable  quantity  of  the 
sesquioxide  ;  citric  and  tartaric  acids  were  not  present,  but  as 
kinic  acid  likewise  prevents  the  precipitation  of  iron  salts  by 
alkalies,  I  tested  for  it,  and  have  obtained  satisfactory  evidence 
of  its  presence,  though  the  quantity  I  had  to  operate  on  was 
too  small  to  obtain  kinone  in  an  isolated  state.  When  the 
precipitate  was  heated  with  diluted  sulphuric  acid  and  binoxide 
of  manganium,  the  peculiar  pungent  odor  of  kinone  was  given 
off,  and  I  obtained  a  slight  yellow  sublimate  for  a  time  ;  boiled 
with  strong  sulphuric  acid  a  grass  green  color  was  produced. 
If  these  reactions  may  be  regarded  as  a  suflScient  proof  of 
kinic  acid  in  the  precipitate  from  ferrated  tincture  of  bark,  the 
probability  is,  that  the  precipitate  from  the  simple  tinctures  also 
contains  it.  But  if  we  look  to  the  importance  in  a  medicinal 
point  of  view  of  the  constituents  of  the  precipitate,  the  alkaloids 
take  the  first  place  ;  next  in  order  the  rufo-cinchotannic  and 
kinic  acids.  Whether  kinic  acid  possesses  any  medicinal 
virtues  at  all,  I  believe  has  not  been  ascertained  yet,  but  the 
advantage  of  retaining  it  in  solution  would  be  to  represent  thus 
the  constituents  of  the  barks  in  their  natural  combina- 
tion. While  the  tinctures  of  our  Pharmacopoeia  aim  at 
this  end,  the  process  is  entirely  unsatisfactory.  If  we  exhaust 
powdered  P  eruvian  bark  by  diluted  alcohol  in  a  displacement 
apparatus  until  the  resulting  tincture  is  free  from  alkaloids, 
alcohol,  subsequently  employed,  will  take  up  another  portion  of 
alkaloids. 
It  is  asserted,  and  I  believe,  correctly,  that  vegetable  material 
treated  by  percolation,  cannot  be  absolutely  exhausted  by  any 
