346 
Oleovcsin  of  Douglas  Fir. 
Am.  Jour.  Pharm. 
June,  1919. 
collectors  travel  through  the  woods  until  they  "  spot "  a  tree  having 
a  cavity  containing  oleoresin.  A  hole  is  bored  into  it  and  the  pocket 
drained,  the  oleoresin  being  conveyed  by  means  of  a  tube  into  suit- 
able containers.  From  one  to  three  gallons  are  frequently  obtained 
from  a  single  boring.  There  is  very  little,  if  any,  evidence  that  a 
given  tree  contains  such  a  pocket,  but  those  who  make  a  livelihood 
as  collectors  claim  to  be  able  to  "  spot "  such  trees  and  they  meet 
with  a  fair  degree  of  success.  It  is  apparent,  however,  that  there 
is  the  element  of  chance  in  such  a  method  and  the  collectors  often 
go  a  whole  day  without  making  a  single  productive  tap. 
It  is  evident  from  the  foregoing  that  the  methods  of  collecting 
this  material  might  possibly  be  improved.  It  might  be  supposed 
that  the  oleoresin  could  be  obtained  by  chipping  the  tree  according 
to  the  method  employed  in  the  South  for  obtaining  ordinary  crude 
turpentine.  This  method,  however,  when  applied  to  Douglas  fir, 
gives  very  little  resinous  material. 
Since  the  oleoresin  tends  to  collect  in  pockets  formed  by  accident 
inside  the  tree,  it  seems  reasonable  to  suppose  it  would  also  tend  to 
collect  in  pockets  formed  by  design.  In  other  words,  the  method 
employed  on  the  slopes  of  the  Alps  for  obtaining  Venice  or  Larch 
turpentine  might  presumably  be  applied  to  advantage  in  securing 
Douglas  fir  turpentine. 
European  Method  a  System  of  Tapping. 
This  method2  is  based  on  the  fact  that  in  the  European  larch  the 
oleoresin  tends  to  collect  in  the  heart  of  the  tree3  and  that  it  often 
fills  the  cavities  made  in  the  trunk  by  frost  or  other  causes.  One 
or  two  holes,  1  to  i1^  inches  in  diameter  and  horizontal  or  nearly 
so,  are  bored  by  means  of  an  auger  early  in  the  spring  in  mature 
trees  about  forty  inches  in  girth.  They  extend  to  the  center  of  the 
tree  and  are  about  a  foot  from  the  ground.  The  holes  are  carefully 
cleaned  and  then  closed  with  a  dry  larch  plug  to  prevent  loss  by 
evaporation.  In  the  autumn  the  cavities  are  emptied  by  means  of 
an  auger.  After  the  second  or  third  collection,  the  holes  are  widened 
to  1.6  inches.  In  some  sections  the  holes  are  not  plugged,  but 
wooden  tubes  are  inserted  in  the  openings  and  the  oleoresin  allowed 
2  "  Die  Osterreicheschen  Alpenlander  und  ihre  Foreste.''  page  369 ;  Arch'w. 
der  Pharmacie  (1900),  page  389. 
3  Botanische  Zcitung,  ly,  pages  329  and  377. 
