248 
CHEMICAL  EXAMINATION  OF   THE  RUBIACEiE. 
kinovic  acid  united  with  a  hydrate  of  carbon,  which  has  the  con- 
stitution of  acetic  acid. 
Cl6Hl307,  caincic  acid=C:8HW,  kinovic  acid4-C4H404. 
Rubichloric  acid,  and  its  separation  into  chlorrubine  and  formic 
acid,  is  a  proof  that  a  process  like  that  above  mentioned  really 
takes  place  in  the  plants.  Citric  acid  =  C  2H6012,  loses  7  equivs. 
of  oxygen  and  passes  into  C12H605,  which,  united  with  the  ele- 
ments of  formic  acid,  produces  rubichloric  acid. 
C14IP09,  rubichloric  acid  =  C,2H6012,  citric  acid  —  O7  +  C2 
H2  O4,  formic  acid. 
At  a  low  temperature  the  deoxidation  of  the  citric  acid  appears 
to  take  place  very  imperfectly.  The  herb  of  Riehardsonia  scabra 
which  was  cultivated  last  summer  by  Prof.  Kosteletzky  in  the  Bo- 
tanic Garden  of  Vienna,  contained  inconsiderable  quantities  of 
tannic  acid,  whilst  not  a  trace  appeared  in  the  roots ;  both  herb 
and  root,  on  the  other  hand,  were  rich  in  citric  acid  salts.  In  its 
native  country,  the  root  of  the  Jtichardsonia  scabra  contains 
tannic  acid. 
The  author  here  adds  some  considerations  on  the  origin  of  the 
hydrates  of  carbon,  and  particularly  on  the  question  from  what 
substances  they  are  produced.  The  fact  that  plants  possess  the 
faculty  of  separating  oxygen  by  the  agency  of  the  sun  light, 
after  they  have  absorbed  carbonic  acid  and  water,  induced  Liebig 
to  suppose  that  the  hydrates  of  carbon  were  formed  from  acids. 
The  absorption  of  carbonic  acid  and  water  and  the  elimination  of 
oxygen  take  place  by  degrees,  and  thus  from  compounds  rich  in 
oxygen,  but  poor  in  carbon  and  hydrogen,  constituents  are  gra- 
dually formed,  always  richer  in  carbon  and  poorer  in  oxygen. 
The  author  considers  the  result  of  his  investigations  as  support- 
ing Liebig's  view,  for  it  proves  that  the  external  resemblance  in  the 
form  of  the  plant  corresponds  also  constantly  with  the  acids  com- 
bined with  various  bases  in  its  interior.  It  is  also  in  favor  of 
this  supposition  that  the  hydrates  of  carbon  are  really  formed 
by  the  process  of  deoxidation  in  the  plants,  that  acids  occur  in 
the  same  plant,  which  with  the  same  amount  of  carbon  and  hy- 
drogen are  distinguished  from  one  another  by  containing  a  larger 
or  smaller  quantity  of  oxygen.  Although  these  acids  cannot  be 
regarded  as  different  oxides  of  one  radical,  it  appears  to  the 
author  to  be  extremely  probable  that  they  may  arise  from  the 
