Production  of  Lemon-Grass  Oil.    { Am.  jour,  pharm. 
J  1       April,  1917. 
DISTILLATION. 
The  apparatus  required  for  the  distillation  of  lemon-grass  oil 
does  not  differ  from  that  in  general  use  for  the  distillation  of  other 
volatile  oils.  Before  distilling  the  plants  it  has  been  found  advis- 
able to  run  them  through  a  fodder  cutter,  in  order  to  permit  closer 
packing  in  the  retort.  From  the  data  at  hand  it  is  estimated  that  if 
the  plants  are  cut  into  2-inch  lengths  a  retort  will  hold  100  pounds  of 
material  for  every  6  cubic  feet  of  space,  but  if  the  plants  are  put  in 
whole  the  quantity  which  the  retort  can  hold  will  be  somewhat  less. 
The  closer  packing,  however,  in  no  way  facilitates  distillation. 
In  a  retort  having  a  capacity  of  30  cubic  feet  a  charge  of  3,000 
pounds  can  be  distilled  in  2  to  2J/2  hours  by  the  steam  which  may  be 
readily  generated  in  a  small  farm  boiler,  and  by  the  use  of  a  larger 
volume  of  steam  the  time  can  be  much  reduced. 
In  this  connection  it  is  interesting  to  note  that  distillation  under 
20  pounds  pressure  in  the  retort  increased  the  yield  of  oil,  but  gave 
an  oil  of  very  dark  color  and  with  lower  citral  content. 
After  the  oil  has  been  distilled  it  should  be  freed  from  water  so 
far  as  possible  in  a  separatory  funnel,  then  dried  by  shaking  with 
anhydrous  calcium  chlorid,  and  filtered.  It  should  be  stored  in  well- 
filled  air-tight  containers  in  as  cold  a  place  as  possible  until  ready 
to  be  shipped  to  market.  The  shipping  can  be  done  in  new  and 
clean  tin  cans  without  injury  to  the  product. 
In  order  to  determine  whether  any  appreciable  quantity  of  oil 
would  be  lost  by  discarding  the  distilled  water  coming  over  with  the 
oil,  a  series  of  tests  was  made  in  191 5.  The  water  from  a  number 
of  charges  of  several  pounds  each  was  retained  and  each  lot  sepa- 
rately redistilled.  In  the  apparatus  used  in  the  experiments  about  1 
gallon  of  water  was  secured  for  each  22  pounds  of  herb  in  the 
charge.  The  average  of  the  results  secured  by  the  redistillation  of 
this  water  showed  that  1.2  gram  of  oil  was  dissolved  in  each  gallon 
of  water,  a  quantity  too  small  to  make  its  recovery  profitable.  Ex- 
amination of  this  recovered  oil  showed  its  characteristics  to  be  prac- 
tically identical  with  the  oil  distilled  directly  from  the  herb. 
VARIETIES. 
During  the  many  years  that  lemon  grass  has  been  cultivated  a 
great  variety  of  forms  of  the  plant  has  been  developed.  Some  years 
ago  an  attempt  was  made  to  divide  the  old  species  into  two  separate 
species,  basing  the  descriptions  partially  on  the  character  of  the  oil 
