720 
Oil  of  Cade 
5  Am.  Jour,  Pharm. 
I       Oct.,  1921. 
The  second  process,  that  of  incomplete  combustion  with  ex- 
clusion of  air,  is  used  for  production  on  a  large  scale.  For  this 
purpose  a  brick  kiln  is  employed,  18  feet  to  22  feet  long  and  about 
6  feet  high,  with  an  inclined  bottom  provided  with  a  gutter,  which 
allows  the  oil  to  drain  into  a  vessel  placed  in  a  pit  in  front  of  the 
exit.  The  kiln  is  covered  with  earth  except  at  the  place  where  the 
cavity  is,  and  for  the  purpose  of  filling  it  up  with  wood  and  setting 
fire  to  the  latter,  large  openings  are  provided  at  the  top  and  sides. 
After  the  fire  is  lighted  these  openings  are  closed,  and  distillation 
proceeds  with  simultaneous  carbonization  of  the  wood.  The  dis- 
tillation frequently  lasts  several  days.  When  the  fire  is  too  hot 
the  resulting  oil  is  more  viscid  and  blacker  than  under  normal  condi- 
tions when  the  color  is  reddish-brown.  The  fresh  distillate  is  left 
standing  for  two  or  three  weeks,  when  it  separates  into  three  layers, 
of  which  the  upper  one  is  the  oil  of  cade,  the  next  is  water,  and  the 
lowest  consists  of  tarry  products.  Such  methods  of  preparation  must 
necessarily  lead  to  variation  in  the  characer  of  the  product. 
According  to  Pepin,  the  specific  gravity  lies  a  little  below  1.000; 
it  makes  a  clear  solution  with  8  to  10  volumes  of  96  per  cent,  alcohol, 
and  in  all  proportions  with  ether,  amyl  alcohol,  chloroform,  acetic 
acid  and  benzene.  The  water-soluble  acid-content  should  not  exceed 
1.5  per  cent,  calculated  as  acetic  acid.  When  distilled  at  ordinary 
atmospheric  pressure  the  fraction  boiling  between  1500  and 
300°  should  amount  to  68  to  80  per  cent.,  whilst  pine  tar  yields  only 
15  per  cent,  between  these  temperatures.  For  the  detection  of  pine 
tar  oil  the  best  test  is  the  copper  acetate  reaction.  One  cc.  of  the 
oil  is  shaken  with  15  cc.  of  petroleum  ether  and  the  mixture  is  then 
filtered.  To  10  cc.  of  the  filtrate  an  equal  volume  of  a  5  per  cent, 
solution  of  copper  acetate  is  added  and  well  shaken,  5  cc.  of  the 
petroleum  ether  layer  is  diluted  with  10  cc.  of  ether  and  filtered.  In 
the  presence  of  pine  tar  oil  the  filtrate  has  an  intense  green  color, 
whilst  pure  cade  oil  gives  a  chestnut-brown  color. 
Cade  oil  of  Spanish  origin,  though  of  low  specfic  gravity, 
contains  a  high  proportion  of  cadinene,  as  shown  by.  fractionation, 
and  does  not  give  a  reaction  for  pine  tar.  It  is  guaranteed  to  be  de- 
rived from  Juniperus  oxycedrns,  and  may,  therefore,  be  accepted  as 
genuine  cade  oil.  The  extreme  limits  for  specific  gravity  I  have  ob- 
served for  this  oil  during  the  last  twenty  years  are  0.955  and  1.064. 
