Am.  Jour.  Pharm.  ) 
December,  1913.  j 
Odorous  Products  in  Plants. 
551 
into  the  inflorescence,  obeying  the  laws  of  diffusion :  a  portion  enters 
into  solution  and,  by  osmosis,  penetrates  into  the  stem.  On  arriving 
in  a  medium  already  saturated  with  similar  products,  a  portion  is 
precipitated,  whilst  the  rest,  consisting  of  a  relatively  soluble  mix- 
ture, continues  to  diffuse  through  the  membranes  and  reaches  the 
organs  of  consumption,  particularly  the  inflorescences. 
At  the  time  when  the  work  of  fertilization  is  accomplished,  a 
certain  quantity  of  essential  oil  is  consumed  in  the  inflorescence. 
It  is  possible  and  even  probable  that  the  green  organs  produce  at  the 
same  time  further  quantities  of  odorous  matters ;  experiment  only 
permits  of  the  determination  of  the  fact  that  the  difference  between 
the  production  and  consumption  is  expressed  by  a  loss  at  the  period 
when  the  functions  of  the  flower  are  accomplished. 
The  practical  consequence  of  this  last  conclusion  is  that  the  har- 
vesting of  the  perfume-yielding  plants  should  be  effected  shortly 
before  this  consumption  takes  place,  that  is,  before  the  act  of  fer- 
tilization. 
When  this  act  has  been  accomplished,  the  odorous  principles 
appear  to  descend  again  into  the  stem  and,  generally,  into  the  organs 
other  than  the  flower,  a  migration  which  is  probably  induced  by 
the  dessication  of  the  inflorescences,  which  involves,  other  things 
being  equal,  an  increase  in  the  osmotic  pressure  and  a  partial  precipi- 
tation in  situ  of  the  least  soluble  principles. 
The  Perfume  in  the  Isolated  Flower. — There  exist,  as  was  sup- 
posed by  J.  Passy  and  as  was  proved  by  A.  Hesse  and  his  collabora- 
tors, two  categories  of  plants :  one  class,  continuing  to  produce  odor- 
ous matters  when  placed  under  conditions  such  that  the  vital  func- 
tions may  still  be  exercised ;  the  other  class,  containing  the  whole  of 
their  odorous  principles  in  the  free  state  and  incapable  henceforth 
of  producing  any  further  quantity,  even  though  their  vitality  be  not 
arrested. 
Evolution  of  the  Odorous  Compounds  and  Its  Mechanism. — 
These  researches,  which  I  have  carried  out  partly  in  collaboration 
with  M.  A.  Hebert,  have  led  to  the  following  conclusions :  The  com- 
pound ethers  (esters)  have  their  origin,  in  particularly  active  fashion, 
in  the  green  portion  of  the  plants,  by  the  direct  action  of  the  acids 
on  the  alcohols  previously  formed.  This  phenomenon  of  esterifica- 
tion  is  assisted  by  a  special  agent  playing  the  part  of  a  dehydrating 
agent,  probably  an  enzyme  of  reversible  activity. 
The  influences  which  are  capable  of  modifying  the  plants  so  as  to 
