THE  AMERICAN 
JOURNAL  OF  PHARMACY. 
AUGUST,  1883, 
ON  THE  CHEMICAL  COMPOSITION  OF  OIL  OF  BIRCH 
(BeTULA  LENTA,  Lin.) 
By  H.  p.  Pettigrew. 
A  contribution  from  the  Cheminal  Laboratory  of  the  Philadelphia  College 
of  Pharmacy. 
A  thorough  chemical  investigation  of  the  composition  of  the  vola- 
tile oil  of  birch  has  never  been  made,  although  in  1844  Procter^  first 
found  it  to  contain  salicylic  acid,  and  from  the  similarity  of  the  pro- 
perties of  this  oil  with  those  of  oil  of  gaultheria  he  suggested  the  idea 
of  an  analogous  chemical  composition  of  the  two  oils. 
Nothing  more  was  written  upon  the  subject  until  1882,  when  Mr. 
G.  W.  Kennedy,^  of  Pottsville,  made  some  experiments  with  it,  by 
which  results  were  obtained,  indicating  the  presence  of  salicylic  acid, 
and  by  which  the  identity  of  the  oil  with  that  of  gaultheria  was  pre- 
sumed. 
In  1843,  Procter  made  a  series  of  experiments  with  oil  of  gaulthe- 
ria, and  in  the  following  year  M.  Cahours^  made  a  careful  analysis  of 
it,  and  found  it  to  consist  of  salicylate  of  methyl,  together  with  10 
per  cent,  of  a  terpene. 
The  oil  used  in  this  analysis  was  obtained  through  the  kindness  of 
Mr.  Kennedy,  and,  being  distilled  by  a  friend  of  his,  an  oil  of  abso- 
lute purity  was  thus  guaranteed. 
The  oil  of  birch  when  freshly  distilled  is  a  bright  and  colorless 
liquid,  of  considerable  refractive  power ;  it  possesses  a  very  agreeable 
and  fragrant  odor,  closely  resembling  that  of  gaultheria,  although  a 
difference  can  be  perceived  when  the  two  oils  are  compared.  With 
age,  the  oil  acquires  a  reddish  color,  of  which,  however,  it  is  deprived 
^  "Am.  Jour.  Phar.,"  2  ser.,  vol.  9,  1844,  page  243. 
"Am.  Jour.  Phar.,"  4  ser.,  vol.  12,  1882,  page  49. 
^"Jour.  de  Phar.  et  Chimie,"  Mai,  1843.    Abstracted  by  "Am.  Jour. 
Phar.,"  2  ser.,  vol.  9,  1844. 
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