Am.  Jour.  Pharna.  \ 
December  1895.  / 
The  Chemistry  of  Rhubarb. 
into  the  market  from  China.  I  am  of  opinion  that  the  red  colora- 
tion in  such  instances  may  be  due  to  emodin,  and  if  that  be  the  case 
an  explanation  might  be  found  of  the  circumstance  that  Grothe15 
appears  to  have  obtained  only  emodin  in  his  examination  of  rhu- 
barb, though  he  incorrectly  took  that  substance  to  be  chrysophanic 
acid.  This  substance  does  not  crystallize  in  prisms,  neither  do  the 
crystals  contain  a  molecule  of  water  as  stated  in  regard  to  the  sub- 
stance described  by  Grothe. 
It  still  remains  to  be  ascertained  whether  the  roots  of  different 
kinds  of  rheum  are  alike  in  containing  the  same  constituents  that  I 
have  obtained  from  Chinese  rhubarb  and  described  in  this  paper; 
also,  whether  there  may  be  further  distinctions  between  them  and 
the  constituents  of  roots  of  varieties  of  Rumex.  In  that  respect  v. 
Thann16  was  of  opinion  that  he  had  proved  the  identity  of  rumicin 
and  chrysophanic  acid ;  but  Rochleder  subsequently  raised  a  ques- 
tion as  to  the  purity  of  the  substances  referred  to.  Moreover,  at 
that  time,  pure  chrysophanic  acid  was  unknown,  and  it  will  now  be 
desirable  to  renew  the  investigation  of  those  varieties  of  Rumex  in 
which  it  is  said  that  chrysophanic  acid  has  been  found.  In  this 
connection  I  must  not  omit  to  mention  that  for  some  months  past 
I  have  been  engaged  upon  the  investigation  of  the  roots  of  Rumex 
nepalensis?  a  native  of  India,  and  that  I  have  found  they  contain 
several  substances,  giving  the  characteristic  reaction  with  caustic 
potash  in  common  with  the  above-mentioned  constituents  of  rhubarb, 
though  they  are  certainly,  like  physcion,  quite  different  substances, 
I  intend  in  a  future  communication  to  deal  with  these  substances 
more  fully. 
Queensland  cherry,  the  fruit  of  an  Euphorbiaceous  plant  {Antidesma  dalla- 
chyanum,  Baill.),  is  also  known  as  the  Herbert  River  cherry.  The  plant  yield- 
ing it  is  a  shrub  or  small  tree,  closely  allied  to  A.  Ghczsembilla,  Gaertn.,  of  the 
Eastern  Archipelago  and  Ceylon.  According  to  Bailey,  "the  fruit,  which,  in 
size,  equals  that  of  large  cherries,  is  of  a  sharp  acid  flavor,  resembling  that  of 
the  red  currant,  which  it  also  equals  when  made  into  jelly.  As  the  European 
fruit  is  placed  among  medicinal  plants,  on  account  of  its  juice  being  grateful 
to  the  parched  palates  of  persons  suffering  from  fever,  this  is  worthy  of  a 
similar  place." — Kezv  Bulletin. 
15  Wiggers'  "  Pharmakognosie,"  1S64,  p.  242,  and  Chem.  Centralbl.,  1S62, 
p.  107. 
16  Annalen  Chem.  Pharm.,  107.  324. 
17  For  a  supply  of  this  material  I  am  indebted  to  the  kindness  of  Mr.  D. 
Hooper,  of  Ootacamuud. 
