548  Oil  of  Andromeda  Lesclienaultii.  {%iri",i87r' 
the  Andromeda  Leschenaultii.  I  did  so,  and  was  enabled  to  identify 
the  oil  as  methyl-salicylic  acid,  and  almost  identical  with  the  Cana- 
dian oil  of  wintergreen. 
Oil  of  wintergreen  is  an  object  of  some  slight  commerce,  being  used 
in  perfumery,  and  occasionally  in  medicine  as  an  antispasmodic.  The 
oil  from  this  Indian  source  contains  less  of  the  peculiar  hydrocarbon 
oil,  which  forms  a  natural  and  considerable  admixture  with  the  Cana- 
dian oil,  and  therefore  is  superior  in  quality  to  the  latter.  The  com- 
mercial demand  for  the  oil  is  not,  however,  considerable  enough  to 
make  its  occurrence  in  India  of  much  direct  importance. 
It  occurred  to  me  in  1869  that  methyl-salicylic  acid  would,  how- 
ever, under  suitable  treatment,  furnish  carbolic  acid  according  to  a 
decomposition  described  by  Gerhardt.  After  a  few  experiments  1 
was  successful  in  preparing  considerable  quantities  of  pure  carbolic 
acid. 
The  method  of  manufacture  is  as  follows : 
The  oil  is  heated  with  a  dilute  solution  of  a  caustic  alkali,  by  which 
means  it  is  saponified  and  dissolved,  methylic  alcohol  of  great  purity 
being  liberated.  The  solution  of  the  oil  is  then  decomposed  by  any 
mineral  acid,  when  beautiful  crystals  of  salicylic  acid  are  formed. 
These  are  gathered,  squeezed,  and  dried.  They  are  then  mixed  with 
common  quick-lime,  or  sand,  and  distilled  in  an  iron  retort ;  carbolic 
acid  of  great  purity,  and  crystallizing  with  the  greatest  readiness, 
passes  into  the  receiver. 
This  acid  is  equal  to  the  purest  kind  obtained  from  coal  tar,  and 
employed  in  medicine.  I  exhibited  a  specimen  of  it  at  the  Neilgherry 
Exhibition  in  1869.  It,  of  course,  possesses  all  the  qualities  w^hich 
have  rendered  this  substance  almost  indispensable  in  modern  medical 
and  surgical  practice. 
I  had  hoped,  from  the  inexhaustible  abundance  with  which  the  plant 
grows  on  the  Neilgherries,  that  the  carbolic  acid  from  this  source  could 
be  prepared  at  less  cost  than  that  imported.  I  have  not  yet  had  an 
opportunity  of  working  on  a  large  scale  with  an  itinerant  still,  as 
would  be  necessary  for  its  cheapest  production ;  but  from  some  calcu- 
lations I  have  lately  made,  I  am  led  to  think  it  can  scarcely  be  pre- 
pared for  less  than  the  price  of  that  procured  from  coal-tar.  The 
purest  kinds  from  the  latter  source  cost  four  shillings  a  pound ;  I 
estimate  the  cost  of  that  from  this  indigenous  source  at  from  rupees 
2*8  to  rupees  3-8  (5  to  7  shillings)  per  pound  in  this  country. 
