506 
ON  LEPTANDRIN. 
hot  add  the  residuum,  slowly  and  gradually,  to  cold  water  equal  to 
two  or  three  times  its  volume.  Allow  this  to  stand  for  seven 
or  eight  days,  when  the  resinous  matter  will  precipitate  to  the 
bottom  of  the  vessel  in  a  semi-fluid  mass,  while  the  water  will 
hold  in  solution  most  of  the  extractive  and  coloring  matter.  Re- 
move this  water,  and  to  the  residue  add  a  fresh  supply  of  cold 
water,  subjecting  it  to  another  washing.  Then  carefully  remove 
the  water,  after  having  allowed  all  the  resinous  matter  to  precipi- 
tate, which  last  must  be  dried  in  shallow  tin  or  porcelain  plates, 
by  a  moderately-continued  heat,  until  it  becomes  perfectly  fria- 
ble on  cooling,  and  which  generally  requires  several  days.  In 
the  preparation  of  this  article  high-proof  alcohol  must  be  em- 
ployed on  account  of  the  large  amount  of  extractive  matter  present, 
which  is  soluble  in  water,and  which  ascending  to  the  proportion  of 
water  employed,  prevents  the  precipitation  of  the  Leptandrin. 
Care  must  be  taken,  likewise,  in  the  application  of  heat,  as  too 
great  a  heat,  say  above  175°  to  180°  F.,  will  render  the  precipi- 
tate inert  or  materially  affect  its  character.  The  above  is  the 
process  usually  employed  in  the  preparation  of  Leptandrin ;  it 
may  be  obtained,  however,  by  adding  the  tincture  to  four  times 
its  weight  of  water,  distilling  off  the  alcohol,  and  setting  aside 
the  residue  for  several  days  until  all  the  Leptandrin  precipitates. 
Remove  the  water  and  dry  the  precipitate  as  above,  having  pre- 
viously worked  it  in  fresh  water  to  remove  extractive,  etc.  Roots 
of  the  second  year's  growth  are  said  to  afford  the  most  Leptan- 
drin. 
History  Leptandrin,  according  to  its  mode  of  preparation  is 
a  jet  black  resinous  substance  resembling  asphaltum,  or  of  a 
greyish  brown  color,  with  a  peculiar  faint  cyanic  smell  and 
taste,  somewhat  bitter  but  not  disagreeable.  In  its  agregate  it 
has  a  vitreous  fracture,  is  unalterable  in  dry  atmosphere,  and 
is  without  acid  or  alkaline  reactions.  Its  powder  has  a  black, 
glistening  soot-like  appearance,  and  coalesces  in  a  warm  moist 
air.  When  first  made,  it  is  soluble  in  alcohol,  though,  as  with 
many  other  resins  when  exposed  to  atmospheric  influence,  it  be- 
comes imperfectly  soluble  in  alcohol,  but  perfectly  so  on  the  ad- 
dition of  aqua  ammonia.  It  is  insoluble  in  water,  but  the  addi- 
dition  of  liquid  potassae  or  ammonia  renders  it  perfectly  soluble, 
from  which  solution  it  is  precipitated  by  acids.  Ether  takes  up  a 
