50 
Oleum  Betuke  Lentw. 
f  Am.  Juur.Pharm, 
X      Feb.,  l88->. 
it  was  one  of  my  objects  in  making  this  visit  to  obtain  tlie  oil  of  birch 
bark^  with  the  view  of  applying  to  it  the  usual  tests  for  oil  of  winter- 
green,  the  result  of  which  will  be  given  further  on. 
The  species  of  birch  used  is  the  Betula  lenta,  commonly  known  in 
this  locality  by  the  names  of  cherry,  sweet  and  black  birch.  It  grows 
to  the  height  of  75  feet ;  but  as  generally  found  is  from  10  to  25  feet 
high.  The  bark  is  very  sweet-aromatic;  the  leaves  are  ovate  or 
oblong-ovate,  form  a  more  or  less  heart-shaped  base ;  acuminate, 
sharply  and  finely  double-serrate ;  when  mature  shining  and  bright 
green  above,  and  glabrous,  except  on  the  veins  beneath.  It  is  found 
in  moist  woods,  and  grows  north  from  New  England  to  Illinois,  and 
along  the  Allegheny  regions  southward. 
The  first  step  in  the  preparation  of  the  oil  is  the  gathering  of  the 
bark,  or  rather  of  the  tr.ee,  as  the  whole  tree  is  used,  except  a  few  small 
sprouts  near  the  ground.  These  are  left  undisturbed,  and  in  5  years 
will  be  found  to  have  grown  to  the  height  of  8  or  10  feet,  and  are 
then  considered  large  enough  to  be  cut  for  the  extraction  of  the  oil. 
It  will  be  observed  that  from  the  stumps  of  trees  used  this  year,  a 
new  growth  may  be  used  5  years  hence,  and  so  on  every  five  years  ; 
this  industry  does,  therefore,  not  involve  the  destruction  of  the  trees, 
as  one  would  naturally  suppose.  The  small  trees  are  preferred,  and 
are  gathered  by  a  man,  for  which  he  is  paid  about  $3.00  per  ton 
delivered,  besides  the  payment  to  the  owners  of  the  land  of  fl.OO  per 
ton  for  the  privilege  of  cutting  the  trees,  making  in  all  $4.00  per  ton 
for  the  trees  delivered  at  the  place  where  the  oil  is  manufactured. 
The  trees  are  then  submitted  to  a  chopping  machine,  containing  2 
large  knives,  about  18  inches  long,  and  3  *to  4  inches  wide,  made 
strong  and  heavy,  and  which  are  so  arranged  that  they  are  operated 
by  a  wheel,  similar  to  that  in  the  ordinary  drug  mill ;  for  every  revo- 
lution of  the  wheel  the  knives  cut  4  times,  and  it  requires  but  a 
short  time  to  cut  a  ton  of  the  material  into  pieces  from  1  to  4  inches 
long,  in  which  condition  they  are  ready  for  the  stills.  These  consist 
simply  of  heavy  wooden  boxes  with  copper  bottoms,  resting  on  a  stone 
foundation,  built  about  15  to  18  inches  above  the  surface  of  the  earthy 
a  place  being  made  for  fire.  Wood  is  used  altogether  for  fuel.  The 
dimensions  of  the  box  or  still  are  4x6  feet  and  3  feet  high. 
The  material  being  ready  for  distillation,  it  is  placed  in  the  still,  as 
much  as  this  will  hold,  and  a  sufficient  quantity  of  water  is  added  to 
fill  the  still  about  one-third  full.    The  still  is  generally  permitted  to 
