596       Recent  Literature  Relating  to  Pharmacy.  {^ecembeSim1, 
from  tonka  beans  containing  about  15  per  cent.,  now  it  is  largely 
produced  by  Perkins'  method  from  salicylic  aldehyde.  In  1879 
crystallized  coumarin  cost  ^12  a  pound  ;  now  it  is  only  about  £if 
chiefly  in  consequence  of  its  production  from  Liatris  odoratissima,  an 
American  plant  containing  it  in  large  amount. 
The  odorous  constituent  of  heliotrope  has  not  yet  been  isolated  ; 
it  is  chemically  related  to  piperine  and  to  safrol,  a  constituent  of 
Japan  camphor  oil,  and  it  was  obtained,  as  piperonal,  by  Haarmann 
&  Reimer  in  1879.  The  price  was  then  about  £j$  per  pound; 
in  ten  years  it  fell  to  nearly  one-tenth,  and  it  is  now  about  a  shilling. 
The  odorous  constituent  of  vanilla  was  first  prepared  artificially  by 
Tiemann  and  Haarmann  in  1 872  from  coniferin,  a  glucoside  occurring 
in  the  cambial  juice  of  Coniferae,  convertible  by  hydrolysis  into 
grape  sugar  and  coniferyl  alcohol  which  yields,  by  oxidation,  the 
aldehyde  vanillin.  Its  manufacture  was  begun  in  1874  by  Haar- 
mann, in  Germany,  and  by  De  Laire  &  Co.,  in  Paris,  but  it  was  at- 
tended with  so  much  difficulty  that  only  a  very  small  quantity  could 
be  produced  at  a  price  in  1876  of  about  £175  per  pound.  However, 
Haarmann  had  observed  that  by  treating  coniferyl  alcohol  with 
melted  potash  it  yields,  among  other  products,  eugenol,  while  Er- 
lenmeyer  found  that  eugenol  heated  with  potassium  permanganate 
yields  vanillin,  and  Tiemann  obtained  a  larger  yield  by  acting  upon 
acet-eugenol.  In  that  way  the  price  of  vanillin  was  reduced  to  about 
£40  per  pound.  A  further  improvement  by  Tiemann  was  the  use 
of  isoeugenol,  by  which  means  the  production  has  been  increased 
to  several  thousand  pounds  a  year,  and  the  price  per  pound  reduced 
to  £$  or  less,  about  one-thirtieth  of  the  price  of  an  equivalent 
quantity  of  vanilla  containing  2  per  cent,  vanillin. 
In  connection  with  the  odor  of  the  rose,  Professor  Schmidt  drew 
attention  to  the  pale  yellow  oil  imported  from  Algiers,  Spain,  the 
South  of  France,  and  the  island  of  Reunion — and  obtained  by  dis- 
tilling varieties  of  geranium  with  steam — as  consisting  essentially 
of  geraniol,  an  alcohol  first  prepared  as  an  article  of  commerce  by 
Heine  &  Co.  This  alcohol  is  also  the  odorous  constituent  of  rose 
oil  and  of  Indian  palmarosa  oil,  obtained  from  Andropogon  schcen- 
anthus.  In  smaller  amounts  it  existfe  in  the  East  Indian  citronella 
oil,  obtained  from  A.  nardus  and  citratus.  Geraniol  is  frequently 
accompanied  by  esters — as,  for  instance,  geranyl  acetate  in  palma- 
rosa oil,  and  in  "petit-grains"  oil.    By  oxidation  it  is  convertible 
