eochlsder's  proximate  analysis. 
83 
and  in  what  ojaantity  t'hey  are  present  therein,  we  seek  in  vain  in  chemi.. 
cal  works. 
As  we  find  only  some  analyses  of  plants  which  possess  a  value,  when-v^e 
examine  the  long  series  of  such  analyses,  so  also  we  search  vainly  for  a 
definite  method  according  to  which  they  could  be  arranged.  There  is  no 
difficulty  in  explaining  why  no  method  is  given  for  the  analysis  of  plants 
such  as  we  possess  in  mineral  chemistry.  Inorganic  analysis  is,  in  gen- 
eral, the  analysis  of  defined  compounds,  the  properties  of  whose  elements 
are,  for  the  most  part,  correctly  known,  and  likewise  the  properties  of  their 
most  important  combinations  with  one  another.  When  the  analysis  of 
plants  treats  of  the  analysis  of  mixtures  which  cannot  be  separated  me  • 
chanically,  then  terminates  the  precision  and  certainty  of  inorganic  chem- 
istry, which  we  only  can  boast  of  in  its  relation  to  elementary  analysis. 
The  investigations  of  the  various  minerals,  as  phonolithe,  &c.,  show  bow 
iittle  we  know  of  the  means  of  separating  the  individual  constituents. 
Every  part  of  a  plant  is  a  mixture  of  many  constituents  not  mechanicfilly 
separable,  the  number  of  contemporaneously  existing  constituents  of  such 
a  mixture  being  infinitely  greater  than  in  the  most  complex  fossils.  If  it 
be  difficult  in  this  case  to  find  out  a  method  of  separation,  how  much  more 
difficult  will  it  be  with  plants,  whose  principal  constituents  are  so  readily 
decomposable  and  changeable  that  they  may  be  altered  not  only  by  the  re- 
agents employed  for  their  separation,  but  act  reciprocally  on  one  another, 
producing  bodies  which  were  not  originally  present. 
When  we  have  to  deal,  in  the  analysis  of  plants,  with  known  compounds, 
as  is  mostly  the  cape  in  mineral  chemistry,  still  the  investigation  is  not 
easy.  In  the  analysis  of  a  vegetable  substance  heretofore  unexamined,  we 
can  reckon  almost  with  certainty  on  meeting  with  one  or  more  quite  on- 
known  bodies.  The  intimation  which  has  been  already  often  expressed, 
that  a  rational  method  for  the  analysis  of  plants  is  quite  impossible  until 
at  least  we  are  correctly  acquainted  with  the  majority  of  vegetable  bodies, 
is,  consequently.,  not  without  some  foundation,  for  only  when  we  know  the 
properties  of  the  constituents  of  plants  and  their  combinations,  can 
method  be  established  which  will  be  available  for  all  time.  Consequent- 
ly, both  for  the  presentand  the  nextcentury  we  must  renounce  the  hope  of  a 
permanent  and  rational  method  of  vegetable  analysis,  as  it  is  scarsely 
possible,  in  a  shorter  space  of  time  for  chemists  to  study  correctly 
and  copiously  enough  the  majority  of  the  constituents  of  plants.  The  num- 
ber of  plants  is  great,  and  increases  yearly  by  fresh  discoveries,  and  with  the 
number  of  plants  the  number  of  peculiar  vegetable  substances  also  increafees. 
Therefore,  if  wt  would  wait  for  the  establishment  of  a  methoi]  of  vegf- 
table  analysis  ^antil  we  are  acquainted  with  the  majority  of  all  vegeta  tie 
bodies,  we  shoiild  never  arrive  at  one,  because  we  can  only  learn  the  proper- 
tiesof  these  bodiee  by  organic  analysis,  and  to  investigate  plants  without  svn:^. 
such  method  of  analysis  tends  to  aimless  researches.  However,  this  is  clear. 
