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  ANNUAL 
  REPORT 
  SMITHSONIAN 
  INSTITUTION, 
  19 
  2 
  9 
  

  

  especially 
  useful 
  owing 
  to 
  their 
  cheapness. 
  Thus, 
  from 
  lemon-grass 
  

   oil, 
  distilled 
  from 
  C. 
  citratus 
  and 
  especially 
  C. 
  flexuosus, 
  the 
  important 
  

   alcohol, 
  citral, 
  is 
  isolated. 
  Palmarosa 
  oil, 
  distilled 
  from 
  C. 
  martini, 
  

   constitutes 
  the 
  main 
  source 
  for 
  the 
  isolation 
  of 
  the 
  alcohol, 
  geraniol, 
  

   one 
  of 
  the 
  constituents 
  of 
  otto 
  of 
  roses. 
  Citronella 
  oil, 
  distilled 
  from 
  

   C. 
  nardus, 
  provides 
  a 
  further 
  source 
  of 
  this 
  alcohol. 
  The 
  aldehyde, 
  

   citronellal, 
  is 
  also 
  isolated 
  from 
  this 
  oil. 
  Another 
  very 
  important 
  

   natural 
  isolate 
  is 
  the 
  phenol-ether, 
  eugenol, 
  obtained 
  from 
  oil 
  of 
  cloves. 
  

   In 
  some 
  instances 
  these 
  "natural 
  isolates" 
  provide 
  starting 
  points 
  for 
  

   the 
  synthetic 
  production 
  of 
  other 
  important 
  odorous 
  substances, 
  of 
  

   which 
  examples 
  will 
  be 
  mentioned 
  later. 
  

  

  So 
  far 
  I 
  have 
  written 
  as 
  though 
  the 
  one 
  object 
  of 
  synthetic 
  chemistry, 
  

   as 
  applied 
  to 
  perfumery, 
  was 
  the 
  production 
  by 
  artificial 
  means 
  of 
  the 
  

   various 
  constituents 
  of 
  floral 
  ottos, 
  in 
  order 
  that 
  by 
  iifiixing 
  these 
  

   together 
  a 
  chemically 
  -exact 
  replica 
  of 
  each 
  and 
  every 
  otto 
  might 
  

   thereby 
  be 
  obtained. 
  This 
  is 
  certainly 
  one 
  objective; 
  but 
  it 
  by 
  no 
  

   means 
  exhausts 
  the 
  field 
  of 
  research 
  and 
  practical 
  achievement. 
  

   In 
  some 
  instances, 
  such 
  as 
  that 
  of 
  otto 
  of 
  roses, 
  chemistry 
  has 
  admi- 
  

   rably 
  succeeded 
  in 
  its 
  task, 
  though, 
  even 
  so, 
  the 
  synthetic 
  ^to 
  suffers 
  

   from 
  the 
  imperfection 
  common 
  to 
  all 
  such 
  preparations, 
  a|id, 
  for 
  the 
  

   production 
  of 
  a 
  scent 
  which 
  is 
  unmistakably 
  that 
  of 
  the 
  ro|e, 
  a 
  small 
  

   proportion 
  of 
  natural 
  material 
  must 
  be 
  added, 
  preferably 
  that 
  obtained 
  

   by 
  enfleurage, 
  or 
  by 
  the 
  extraction 
  of 
  roses 
  with 
  petroleum 
  eiher. 
  

  

  Speaking 
  generally, 
  how^ever, 
  it 
  may 
  be 
  said, 
  in 
  reference 
  to 
  this 
  

   task, 
  that 
  chemistry, 
  while 
  so 
  far 
  not 
  always 
  successful 
  in 
  soVing 
  the 
  

   problem, 
  has 
  done 
  more 
  than 
  this. 
  In 
  some 
  instances, 
  natu-al 
  per- 
  

   fume 
  materials 
  have 
  up 
  to 
  date 
  eluded 
  analysis, 
  and 
  ther 
  exact 
  

   chemical 
  composition 
  remains 
  unknown. 
  This 
  is 
  the 
  case 
  w|th 
  am- 
  

   bergris, 
  an 
  important 
  perfume 
  of 
  animal 
  origin 
  ; 
  or, 
  to 
  take 
  an 
  ijistance 
  

   of 
  a 
  plant 
  perfume, 
  the 
  exact 
  constitution 
  of 
  the 
  campho^ceous 
  

   alcohol 
  which 
  is 
  the 
  main 
  constituent 
  of 
  oil 
  of 
  patchouh 
  still 
  i^mains 
  

   mysterious. 
  \ 
  

  

  These 
  are 
  only 
  two 
  instances 
  out 
  of 
  many, 
  and 
  much 
  research 
  

   remains 
  to 
  be 
  done 
  before 
  it 
  will 
  be 
  possible 
  to 
  say 
  that 
  the 
  pel-fume 
  

   of 
  plants 
  has 
  yielded 
  up 
  its 
  last 
  secret. 
  In 
  some 
  cases, 
  howe\jer, 
  in 
  

   which 
  it 
  has 
  not 
  yet 
  been 
  possible 
  to 
  prepare 
  synthetically 
  a 
  sub^ance 
  

   identical 
  with 
  the 
  natural 
  product, 
  research 
  has 
  ultimated 
  ik 
  the 
  

   discovery 
  of 
  substances 
  resembling 
  this 
  product 
  in 
  odor 
  with 
  aisufE- 
  

   cient 
  degree 
  of 
  exactitude 
  to 
  take 
  its 
  place, 
  to 
  a 
  greater 
  or 
  esser 
  

   extent, 
  in 
  the 
  art 
  of 
  perfumery. 
  

  

  An 
  important 
  example 
  is 
  provided 
  by 
  musk, 
  the 
  exact 
  chemical 
  

   composition 
  of 
  which 
  is 
  doubtful, 
  though 
  the 
  main 
  odorous 
  prin- 
  

   ciple 
  would 
  appear 
  to 
  be 
  a 
  methyl-cyclo-penta-decanone. 
  Se[^eral 
  

   synthetic 
  "musks" 
  have 
  been 
  prepared, 
  exhaling 
  the 
  deli^tful 
  

   fragrance 
  of 
  this 
  exquisite 
  perfume, 
  which 
  can 
  be 
  obtained 
  far 
  here 
  

  

  