Am.  jour,  pharm.  \    Production  of  Lemon-Grass  Oil. 
April,  1917.      J  J 
189 
general  could  thus  be  detected,  but  at  the  present  time,  when  the 
valuation  of  the  oil  is  entirely  on  the  basis  of  the  citral  content,  it 
is  difficult  to  understand  the  reason  for  the  continued  use  of  the 
solubility  test.  It  has  been  shown  repeatedly  that  in  many  parts  of 
the  world  pure  lemon-grass  oil  does  not  pass  the  solubility  test, 
especially  after  it  has  been  stored  for  several  months.  This  has 
been  true  of  most  of  the  samples  of  the  oils  produced  in  the  Western 
Hemisphere,  so  that  West  Indian  lemon-grass  oil  has  come  to  be  a 
synonym  for  insoluble  oil.  This  discrimination  has  kept  out  of  the 
market  many  West  Indian  oils  of  very  high  citral  content. 
There  has  been  much  discussion  regarding  the  factors  which 
affect  the  solubility  of  the  oil,  it  having  been  contended  that  the 
length  of  time  of  distillation  is  the  controlling  factor.  In  order  to 
secure  data  upon  this  point  the  following  tests  were  made:  In  1914, 
158  pounds  of  the  freshly  cut  plants  were  distilled  with  steam  and 
the  oil  drawn  off  in  fractions  at  intervals  of  45  and  60  minutes,  re- 
spectively. The  first  fraction  represented  a  yield  of  oil  of  0.28  per 
cent.,  the  citral  content  of  the  oil  being  80  per  cent.,  while  the  second 
fraction  represented  a  yield  of  0.04  per  cent,  of  oil,  with  a  citral 
content  of  85  per  cent.  When  first  distilled  the  first  fraction  gave 
a  slightly  cloudy  solution  with  three  volumes  of  70  per  cent,  alcohol, 
but  after  two  months  it  gave  a  very  cloudy  solution  in  all  volumes 
of  70  per  cent,  alcohol.  The  second  fraction  was  soluble  with  clear 
solution  in  three  volumes  of  70  per  cent,  alcohol,  showing  no  sign 
Table  VI. 
Citral  Content  and  Solubility  in  70  Per  Cent.  Alcohol  of  Various  Fractions 
of  Lemon-grass  Oil. 
Fractions. 
Yield  of 
Oil. 
Citral 
Content  of 
Oil. 
Solubility  in  70  Per^Cent  Alcohol. 
Per  Cent. 
Per  Cent. 
First  15  minutes  .  .  . 
0.21 
39 
Soluble  with  very  cloudy  solution  in  two 
volumes  and  over. 
15  to  30  minutes.  .  . 
.21 
74 
Soluble  in  clear  solution  in  two  volumes 
and  over. 
30  to  50  minutes.  .  . 
•05 
82 
Do. 
50  to  90  minutes.  .  . 
.01 
80 
Do. 
of  change  after  two  months.  Another  sample  of  203  pounds  of  the 
fresh  plants  distilled  with  steam  and  the  oil  drawn  off  in  fractions 
at  intervals  of  15,  30,  50,  and  90  minutes,  respectively,  gave  the 
results  shown  in  Table  VI. 
