24 
PRECIPITATED  CARBONATE  OF  IRON. 
color,  reddening  litmus  freely,  and  had  a  bitter  taste.  This  was 
evaporated  to  a  soft  extract,  and  treated  with  boiling  water.  A 
yellow  mass,  consisting  of  wax,  fatty  matter,  resin  and  brilliant 
yellow  coloring  matter  remained  undissolved,  the  latter  having 
a  bitter  and  nauseous  taste,  and  partially  soluble  in  chloroform, 
oil  of  turpentine  and  alcohol.  The  watery  liquid  was  filtered 
until  transparent ;  it  had  a  sharp  acid,  scarcely  bitter  taste,  and 
on  evaporation  afforded  no  crystalline  matter.  The  clear  watery 
acid  liquid  gave  a  clear  olive  green  color  with  sesquichloride  of 
iron,  and  a  bright  emerald  green  with  sulphate  of  copper. 
Nitrate  of  mercury,  solution  of  gelatin  and  a  solution  of  an  al- 
kaloid occasioned  no  change.  These  reactions  prove  that  the 
acid  is  not  tannic  or  gallic,  and  that  it  is  probably  an  acid  pecu- 
liar to  this  plant.  Various  experiments  were  made  with  a  view 
of  isolating  it  without  success. 
When  the  alcoholic  extract  was  dissolved  in  water  and  pre 
cipitated  with  subacetate  of  lead,  and  the  filtered  liquor  deprived 
of  lead  by  sulphuretted  hydrogen  and  evaporated,  an  extract  of 
a  pure  bitter  taste  results,  which  is  chiefly  bitter  extractive* 
The  root  after  extraction  by  alcohol  and  drying,  was  percolated 
with  cold  water.  The  percolate  was  nearly  black  from  its  depth 
of  color,  had  a  sweetish  mucilaginous  taste,  and,  on  standing  a 
short  time,  formed  quite  a  firm  jelly,  which  proved  to  be  pectin 
associated  with  glucose. 
The  chemical  constitution  of  this  root  is  evidently  allied  to 
that  of  gentian,  and  has  nothing  in  common  with  columbo  except 
its  bitterness,  and  this  is  due  to  another  principle.  American 
gentian  is,  therefore,  a  more  appropriate  name  than  American 
columbo. 
NOTE  ON  A  SOPHISTICATED  PRECIPITATED  CARBONATE  OF 
IRON. 
Mr.  Editor, — The  following  notes,  which  I  made  at  the  time, 
are  at  your  disposal : 
In  preparing  Muriated  Tincture  of  Iron  recently,  I  was  much 
annoyed  at  the  insolubility  of  the  Prec.  Carb.  Iron,  a  new  lot 
which  I  had  just  received.  After  a  prolonged  digestion  of  3 
ounces  for  five  or  six  hours  with  the  requisite  amount  of  muri- 
