-Am.  Jour.  Pharm. 
Dec,  1891. 
Salix  Lucida. 
58i 
where  the  water  and  oil  separate,  the  oil  going  to  the  bottom  being 
heavier ;  and  the  water  being  lighter  and  in  excess,  passes  through 
the  pipe  into  a  larger  receiver,  where  it  is  reserved  for  the  macera- 
tion of  the  next  quantity  of  birch  to  be  distilled.  This  is  repeated 
a  number  of  times  before  fresh  water  is  used. 
The  yield,  which  is  about  one  per  cent.,  is  most  abundant  during 
the  months  of  July  and  August. 
On  taking  a  sample  of  the  oil  from  the  receiver  only  a  short  time 
after  the  separation  of  the  water,  I  found  the  specific  gravity  to  be 
1*17 ;  another  sample  from  the  same  distillate,  which  was  allowed 
to  stand  between  48  and  60  hours,  so  as  to  get  more  thoroughly 
separated,  had  the  specific  gravity  ri8,  which  I  think  conclusively 
proves  that  the  lower  specific  gravity  of  pure  oil  of  birch  is  due  to 
water  imperfectly  separated. 
The  color  of  oil  of  birch  when  first  distilled  is  very  light  or 
almost  colorless,  but  on  standing  a  while  becomes  very  much 
darker.  Occasionally,  the  oil  is  found  to  be  highly  colored,  due  to 
traces  of  iron  from  the  oxidation  of  the  tin  worm  or  the  can  with 
which  the  oil  comes  in  contact. 
There  are  three  ways  of  clearing  the  oil :  by  decolorization,  filtra- 
tion and  redistillation.  The  easiest  method  is  decolorization,  by 
putting  the  oil  in  a  bottle,  adding  a  few  crystals  of  citric  acid  and 
agitating  occasionally,  until  the  oil  is  colorless,  or  nearly  so. 
See  also  paper  on  the  distillation  of  oil  of  birch  in  Amer.  Jour. 
Pharmacy,  1882,  p.  49. 
SALIX  LUCIDA,  Muhlenberg. 
Shining  Willow. 
By  Robert  W.  Beck,  P.G. 
Contribution  from  the  Chemical  Laboratory  of  the  Philadelphia  College  of  Pharmacy- 
No.  98. 
This  species  of  willow  is  a  shrub  or  Small  tree  ten  to  twenty-five 
feet  in  height,  and  is  found  along  the  banks  of  streams  from  New 
England  to  Pennsylvania  and  westward.  According  to  Gray  it  is 
closely  allied  to  the  S.  pentandra  of  Europe.  The  material  for  the 
following  investigation  was  collected  by  the  author  in  the  western 
part  of  Pennsylvania. 
