AmAp?iir'i9i3arm" }•     Constituents  of  Taraxacum  Root.  173 
and  extracted  with  aqueous  ammonium  carbonate.  On  subsequently 
evaporating  the  ether  there  remained  a  slight  residue,  from  which 
a  crystalline  substance  melting  at  233 — 235 0  was  obtained.  This 
substance  was  very  soluble  in  chloroform,  almost  insoluble  in  ethyl 
acetate,  and  gave  no  coloration  with  ferric  chloride,  but  the  amount 
obtained  (0.04  gram)  was  too  small  to  permit  of  its  further  exam- 
ination. The  ammonium  carbonate  extract,  when  acidified  and 
extracted  with  ether,  yielded  a  small  amount  of  a  semi-crystalline 
product,  which  was  readily  soluble  in  warm  water,  and  its  solution 
gave  with  ferric  chloride  a  deep  green  color.  The  whole  of  this 
product  was  heated  with  chloroform  containing  a  trace  of  ethyl 
acetate,  when  a  small  amount  of  a  brown  substance  remained  undis- 
solved. The  latter  was  crystallised  from  very  dilute  alcohol,  when 
0.07  gram  of  an  acid  was  obtained,  which  melted  and  decomposed 
at  2140,  and  gave  a  deep  green  color  with  ferric  chloride.  This 
substance  was  evidently  3 : 4-dihydroxycinnamic  acid,  since  .  no 
depression  of  the  melting  point  ensued  when  mixed  with  a  pure 
specimen  of  the  respective  acid,  and  it  was  subsequently  obtained 
in  an  amount  which  permitted  of  its  complete  identification,  as 
will  be  further  noted.  The  portion  of  the  above-mentioned  product 
which  had  dissolved  in  the  mixture  of  chloroform  and  ethyl  acetate 
formed,  after  the  evaporation  of  the  solvent,  a  viscid  mass,  which 
was  repeatedly  extracted  with  boiling  benzene.  From  the  latter 
liquid  some  crystals  were  deposited,  which,  after  several  crystallisa- 
tions from  benzene  containing  a  little  alcohol,  separated  in  flat 
needles  melting  at  145 — 1460.  This  substance  amounted  to 
0.25  gram,  and  was  identified  as  />-hydroxyphenylacetic  acid. 
(Found,  C  =  62.6;  H  — ■  5.4.    Calc,  C  =  63.1;  H  =  5.3  per  cent.) 
After  the  extraction  of  the  original  aqueous  liquid  with  amyl 
alcohol,  as  above  described,  the  last  traces  of  the  latter  were  removed 
by  a  current  of  steam.  The  liquid  was  then  treated  with  a  solution 
of  basic  lead  acetate  until  no  further  precipitate  was  produced, 
the  precipitate  collected  and  thoroughly  washed  with  water,  the 
washings  being  added  to  the  main  portion  of  the  filtered  liquid. 
Isolation  of  3  :  4-Dihydroxycinnamic  Acid, 
C8H8(OH)2.CH :  CH.002H. 
A  portion  of  the  above-mentioned  basic  lead  acetate  precipitate, 
representing  2  kilograms  of  the  original  alcoholic  extract,  was  sus- 
pended in  water,  decomposed  by  hydrogen  sulphide,  and  the  mixture 
