Am  Jour.  Pharm. ) 
Nov.,  1884.  ; 
Chemistry  o  f  Plants. 
581 
.CHEMISTRY  OF  PLANTS. 
By  M.  Ballo. 
The  author  previously  showed  that  in  aqueous  solution  of  carbonic 
anhydride,  the  latter  exists  as  hydroxide,  and  he  concludes  therefore 
that  this  is  the  form  in  which  it  becomes  assimilated  by  plants.  He 
finds  that  the  reduction  of  carbonic  anhydride  to  formic  acid  can  be 
effected  not  only  by  the  action  of  potassium  on  the  moist  gas,  but  also 
by  the  action  of  an  energetic  reducing  agent  (sodium-amalgam)  on 
alkaline  hydrogen  carbonates,  and  on  calcium  hydrogen  carbonates, 
this  being  of  interest  in  connection  with  plant  chemistry  through  the 
wide  distribution  of  the  later  salt  in  water.  Glycollic  acid,  which  has 
been  shown  to  occur  in  unripe  grapes,  and  also  tartaric  acid  have  been 
obtained  by  the  reduction  of  oxalic  acid  (Bull.  Soe.  Chim.,  vol.  27,  p. 
3;  Annalen,  vol.  166,  p.  124).  Tartaric  acid  has  likewise  been  shown 
by  Liebig  and  others  to  be  an  oxidation-product  of  most  of  the  carbo- 
hydrates, and  by  reversing  the  process  (i.  e.,  by  reduction)  it  might 
therefore  be  better  suited  to  the  formation  of  these  substances  than 
carbonic  acid.  Whilst  a  portion  of  the  oxalic  acid  of  plants  serves  to 
decompose  calcium  sulphate,  by  far  the  greater  portion  must  give  rise 
to  the  production  of  glycollic  and  tartaric,  or  of  malic  and  succinic 
acids.  The  conversion  of  formic  acid  (which  is  assumed  to  be  the 
first  reduction-product  of  carbonic  acid)  into  oxalic  acid  in  plants, 
is  probably  brought  about  by  nitric  acid  ;  it  is  found  that  nitric  acid 
does  effect  this  conversion  if  the  reaction  be  stopped  when  red  fumes 
begin  to  be  evolved.  The  author  believes  that  this  is  the  reason 
why  nitrogen  must  be  presented  to  plants  in  the  form  of  nitrates;  a 
portion  of  this  is  no  doubt  reduced  to  ammonia,  a  second  portion  pro- 
bably to  nitrous  acid,  whilst  the  greater  part  is  reduced  to  nitric  oxide, 
which,  by  the  action  of  oxygen  and  water,  becomes  reconverted  into 
nitric  acid. 
The  reduction  of  oxalic  to  tartaric  acid  may  be  assumed  to  be 
effected  by  the  coalition  of  two  oxalic  acid  molecules,  or  of  one  mole- 
cule oxalic  acid  with  one  molecule  glycollic  acid ;  whilst  the  produc- 
tion of  acids  containing  an  uneven  number  of  CH.OH- groups  can  be 
explained  by  formic  acid  taking  part  in  the  reaction.  By  the  further 
reduction  of  the  acids,  alcohols  are  produced.  It  is  not  yet  understood 
in  what  way  the  salts  act  in  the  vegetable  and  animal  organisms,  but 
