Am.  Jour.  Pharm. 
June,  1919. 
Oleoresin  of  Douglas  Fir. 
347 
to  flow  through  them  into  suitable  receptacles.4  The  production 
once  begun  entails  little  labor  and  the  product  obtained  is  quite  pure. 
The  trunk  of  the  tree  is  injured  but  little  and  the  same  cavities  are 
said  to  yield  oleoresin  for  twenty5  to  fifty6  years. 
Combined  Cruiser  and  Tapping  System. 
The  European  method  might  be  used  to  advantage  in  combina- 
tion with  the  "  cruiser  method  "  mentioned  above  by  plugging  the 
tap  from  which  no  oleoresin  flows  immediately  and  draining  the  tap 
the  following  season  or  sooner  if  the  accumulation  of  oleoresin 
takes  place  rapidly  enough.  The  labor  involved  in  making  the  tap 
would  not  then  be  entirely  lost.  Instead  of  being  plugged,  the  tap 
might  be  connected  to  some  suitable  container  and  allowed  to  drain 
for  a  given  period.  In  that  case  care  should  be  taken  through  the 
use  of  a  closed  vessel  to  prevent  loss  from  evaporation.  In  addition 
to  living  trees,  the  stumps  of  recently  felled  trees  may  often  be 
tapped  to  advantage. 
Commercial  Uses  of  Oleoresins. 
The  demand  for  Oregon  fir  balsam  seems  to  be  on  the  increase, 
as  indicated  by  the  present  (February  1,  1919)  market  price  of 
$1.75  to  $1.80  per  gallon,  as  compared  with  $1.15  to  $1.25  some  time 
ago.  This  increase  in  price  has  been  the  result  of  increased  do- 
mestic demands,  as  there  has  been  little,  if  any,  export  trade  in  this 
article  since  the  beginning  of  the  war.  The  domestic  consumption 
is  on  the  increase  and  this  is  due  apparently  to  a  greater  use  of  this 
material,  particularly  by  the  varnish  trade.  Oregon  fir  balsam  is 
also  being  used  to  some  extent  as  a  substitute  for  Venice  turpentine, 
a  purpose  for  which,  under  the  name  of  Douglas  fir  turpentine,  it 
was  suggested  by  the  Forest  Products  Laboratory  about  two  years 
ago.  As  such  it  is  employed  particularly  in  the  ceramics  industry 
and  in  the  manufacture  of  porous  plasters. 
In  addition  to  these  uses,  it  is  probably  employed  to  some  extent 
also  in  the  place  of  Canada  balsam.  The  term  "  balsam,"  however, 
as  applied  to  both  of  these  articles,  is  a  misnomer,  since  they  are 
not  balsams  but  turpentines.    Oregon  fir  balsam  has  been  regarded 
4  Duhamel,  "  Traite  des  Arbres,"  II,  page  355. 
5  Tschirch,  "Die  Harze  und  die  Harzbehalter  "  (1906),  page  614. 
6  G.  Planchon  et  E.  Collin,  "  Les  Drogues  simples  d'origine  Vegetable,"  1, 
page  70. 
