474  Gombcrgs  Extraction  Apparatus.  o^r^xm' 
leaves  a  black  residue.  It  is  also  insoluble  in  HC1,  completely  solu- 
ble, however,  in  concentrated  H2S04,  forming  a  very  dark  red  solu- 
tion from  which  the  resin  is  entirely  precipitated  as  a  flocculent,  red 
powder,  on  the  further  addition  of  a  quantity  of  water.  On  allowing 
the  liquid  to  stand,  the  resin  rises  to  the  top,  leaving  the  colorless 
solution  at  the  bottom.  When  shaken  up,  the  mixture  has  much 
the  appearance  that  is  produced  when  Tr.  Cinchon.  Comp.,  U.  S.  P., 
'80,  is  mixed  with  water. 
The  resin  is  also  soluble  in  HN03,  from  which  it  is  only  partially 
precipitated  on  the  addition  of  water.  After  allowing  it  to  stand,  the 
underlying  liquid  was  still  highly  colored,  in  which  it  differed  from 
that  of  former  test. 
For  an  examination  of  the  precipitate  in  tincture  of  sanguinaria, 
see  also  paper  by  F.  L.  Slocum  in  Amer.  Jour.  Phar.,  1 88 1 ,  p.  277. 
GOMBERG'S  EXTRACTION  APPARATUS. 
By  Harry  Kahn,  Ph.  M. 
This  apparatus  which  is  for  the  continuous  extraction  of  compara- 
tively large  quantities  of  drug,  was  constructed  by  Moses  Gomberg, 
B.  Sc.,  Assistant  in  Organic  Chemistry  in  the  University  of  Michi- 
gan, in  the  chemical  laboratory  of  which  institution  it  has  been  in 
almost  constant  use  for  the  last  three  years. 
It  consists  of  an  ordinary  conical  glass  percolator  a,  of  about  two 
litres  capacity ;  the  upper  opening  is  fitted  with  a  circular  piece  of 
board  b,  which  is  about  2-54  cm.  thick,  and  after  it  has  been  covered 
with  chamois-skin  or  other  suitable  material,  should  fit  tightly  into  the 
percolator.  In  the  centre  of  the  board  b  is  a  hole  to  admit  a  rubber 
stopper  through  which  one  arm  of  the  J-tube  c  is  inserted,  the  upper 
arm  being  connected  by  means  of  rubber  tubing  to  an  upright  Liebig's 
condenser  d,  to  the  upper  end  of  which  is  attached,  by  means  of  rub- 
ber tubing,  a  small  funnel  e  to  facilitate  the  addition  of  menstruum. 
The  other  arm  of  the  J-tube  c  is  connected  by  means  of  rubber  tubing 
to  the  hard  glass  tube  f  a?id /',  which  is  about  I  cm.  inside  diame- 
ter, and  is  so  bent  that  /is  25  cm.  long  and  f  45  cm.  To  the  lower 
opening  of  the  percolator  is  attached,  by  means  of  rubber 
tubing,  a  short  piece  of  combustion  tubing  k,  which  is  drawn  out  to 
allow  a  piece  of  hardglass  tubing  p  and  p' ,  1  cm.  internal  diameter, 
to  be  attached.     The  tube  p  and  p'  is  bent  so  as  to  form  a  syphon 
