RESEARCHES  ON  THE  RESPIRATION   OF   FLOWERS.  35 
Now,  all  plants  being  composed  of  several  distinct  parts,  it 
may  be  asked,  » What  part  is  taken  by  each  portion  in  the 
production  of  the  phenomenon  ?"  To  ascertain  this,  it  is  ne- 
cessary to  anatomize  the  flower — to  isolate  its  various  parts,  to 
study  the  part  each  plays — by  putting  them  respectively  in 
contact  with  known  volumes  of  normal  air — taking  their  respec- 
tive weights  into  consideration — and  comparing  the  results 
given  by  the  various  parts,  with  the  general  results  derived 
from  the  entire  plant,  the  experiment  being,  moreover,  effected 
under  perfectly  identical  circumstances. 
By  operating  thus  on  flowers  with  sufficiently  developed  pistil 
and  stamens,  the  weight  of  which  is  not  a  fraction  too  small  for 
that  of  the  entire  flower  and  the  corolla,  such  as  the  oriental 
poppy,  the  field  coquelicot,  the  coquelicot  with  large  bracts,  the 
lily,  the  water  lily,  &c,  I  found  that  on  comparing  the  propor- 
tion of  carbonic  acid  furnished  by  the  corolla  with  that  given, 
under  the  same  conditions,  by  the  pistil  and  stamens,  there  was 
a  great  difference  in  favor  of  the  latter — a  result  which  might, 
indeed,  have  been  expected. 
Finally,  independently  of  the  carbonic  acid  formed  by  the 
combustion  of  the  elements  of  the  flower  at  the  expense  of 
atmospheric  oxygen,  this  gas  itself  disengages  a  certain  pro- 
portion, as  may  be  ascertained  by  leaving  the  flowers  in  an  ap- 
paratus containing  inert  gases,  such  as  hydrogen  or  nitrogen. 
In  conclusion,  I  summarize  thus  : — 
1.  That  all  flowers  left  in  a  limited  atmosphere  of  normal  air 
consume  oxygen,  and  produce  carbonic  acid  in  proportions 
varying  as  the  flower  is  scentless  or  not. 
2.  That  the  circumstances  under  which  the  phenomenon 
takes  place  being  identical,  the  proportion  of  carbonic  acid 
increases  as  the  temperature  is  raised. 
3.  That  generally  with  flowers  from  the  same  plant  and  of 
equal  weight,  the  quantity  of  carbonic  acid  produced  is  rather 
greater  when  the  apparatus  in  which  the  experiment  is  per- 
formed is  exposed  to  the  light,  than  when  it  is  in  darkness  ;  that 
the  proportion  is,  nevertheless,  sometimes  the  same  under  either 
condition. 
4.  That  when  the  normal  air  is  replaced  by  pure  oxygen,  the 
differences  become  much  more  marked. 
