194 
TINCTURE  AND  FERRATED  TINCTURE  OF  BARK. 
with  diluted  alcohol,  until  this  ceases  to  take  up  anything,  the 
residue  upon  the  filter  is  insoluble  in  water  and  possesses 
scarcely  any  taste ;  but  when  it  is  now  treated  with  acidulated 
water,  a  slightly  colored  solution  is  obtained,  which,  besides 
some  cinchonic  red,  contains  quinia  and  quinidia.  For  if  this 
solution  is  supersaturated  with  ammonia,  and  then  agitated  with 
ether,  the  ether  on  evaporation  leaves  a  residue  which  is  partly 
gumlike,  partly  of  a  crystalline  structure,  and  gives  with  chlo- 
rine water  and  ammonia  the  characteristic  green  color  of  those 
two  alkaloids. 
The  result  is  the  same,  whether  tincture  of  red  or  yellow  bark,  or 
any  compound  tincture  of  either  kind,  is  employed.  I  have  also 
examined  several  precipitates  from  ferrated  tincture  of  bark,  and 
have  discovered  the  alkaloids  in  every  instance.  Of  some  of 
these  last  named  tinctures  I  did  not  learn  the  process^  but 
among  my  notes  I  find  that  the  precipitate  which,  on  standing, 
had  been  separated  from  the  ferrated  tincture  prepared  by  its 
originator,  Mr.  Simes,  contained  the  alkaloids.  I  have  likewise 
obtained  them  from  the  tincture  prepared  by  myself,  by  sesqui- 
oxide  of  iron  and  ammonio-tartrate,  or  citrate  of  iron,  instead  of 
the  ammonio-citrate,  and  from  the  precipitate  occasioned  in 
tincture  of  bark  by  an  acid  solution  of  citrate  of  iron.  In  view 
of  the  uniformity  of  the  results  obtained  by  many  experiments, 
I  can  therefore  assert,  that  the  precipitates  separating  from  the 
various  simple,  compound  and  ferrated  tinctures  of  bark  contain 
a  portion  of  the  alkaloids  in  a  state  insoluble  in  water  and 
diluted  alcohol. 
The  precipitate  obtained  from  a  simple  tincture  of  bark,  after 
it  has  been  washed  with  diluted  alcohol,  and  treated  with  acidu- 
lated water,  consists  chiefly  of  cinchonic  red  ;  it  is  insoluble  in 
water,  scarcely  soluble  in  ether,  freely  soluble  in  strong  alcohol 
and  reprecipitated  by  water;  it  is  dissolved  by  caustic  alkalies 
with  a  deep  blood-red  color,  and  precipitated  by  acids,  in  the 
form  of  brownish  red  floccules;  the  alkaline  solution  neutralized 
as  nearly  as  possible,  produces  a  purplish  brown  precipitate 
with  acetate  of  lead  and  a  yellowish  brown  with  sesquichloride 
of  iron.  The  cinchonic  red  has  the  behaviour  of  a  weak  acid  ; 
and  inasmuch  as  it  is  formed  according  to  Schwartz,  by  the 
oxidation  of  cinchotannic  acid,  I  propose  for  it  the  name  of 
