504 
Shellac. 
Am.  Jour.  Pharm. 
Oct.,  1888. 
are  curved  and  barely  half  an  inch  in  length.  It  may  be  here  remarked 
that  a  very  similar  plant^  but  with  smaller  and  yellowish  flowers,  has 
been  grown  at  the  Botanical  Gardens  at  Regents  Park  for  the  last 
eighteen  years  under  the  name  of  L  anisatum,  but  the  leaves  of  this 
species  have  a  sassafras  taste.  They  differ  from  those  of  L  religiosum 
in  having  the  midrib  prominent  below  and  depressed  on  the  upper 
surface  of  the  leaf,  while  in  I.  religiosum  the  midrib  is  prominent  on 
the  upper  and  not  on  the  lower  surface,  and  the  taste  is  astringent  and 
terebinfhinous. — Phar.  Jour,  and  Trans.,  August  11,  page  101. 
SHELLAC.^ 
By  R.  Benedikt  and  E.  Ehrlich. 
When  shellac,  previously  freed  from  fat  by  boiling  with  sodium 
carbonate,  is  boiled  with  caustic  alkalis  for  two  hours,  and  the  cold 
solution  acidified  with  sulphuric  acid,  about  70  per  cent,  of  a  viscous, 
liquid  shellac  is  precipitated.  The  product  is  extracted  with  ether,  and 
purified  by  means  of  the  magnesium  salt  (C^6^^7o^%2^i3)-  1^  is  a 
thick,  viscous  liquid,  which  becomes  mobile  when  heated,  and  is  only 
very  sparingly  soluble  in  boiling  water,  but  dissolves  readily  in  alcohol 
and  ether.  The  alcoholic  solution  is  precipitated  by  water.  When 
heated,  water  is  evolved  and  on  cooling  a  solid  mass  very  similar  to 
ordinary  shellac  is  obtained.  The  acid  value  of  liquid  shellac  is  nearly 
three  times  as  great  as  that  of  ordinary  shellac,  1  gram  requiring  0*204 
gram  of  potash  for  complete  saturation.  From  this  datum  and  from 
the  elementary  analysis,  the  formula  of  liquid  shellac  is  probably 
^'46^72012.  A  mixture  of  ordinary  and  liquid  shellac  is  obtained  by 
boiling  two  portions  of  shellac,  one  with  sodium  carbonate,  the  other 
with  soda,  separating  the  wax  and  acidifying  the  cold  mixed  solutions 
with  acetic  acid.  It  is  a  plastic  resin  which  when  free  from  acid 
retains  its  plastic  condition  for  a  considerable  time,  but  after  several 
months  gradually  begins  to  harden  at  the  surface.  The  alkaline-earth 
salts  of  liquid  shellac  are  soluble  in  cold  water  in  all  proportions,  they 
are  precipitated  as  thick  liquids  when  the  solution  is  boiled,  but  redis- 
solve  completely  on  cooling.  When  an  aqueous  solution  is  evaporated 
over  sulphuric  acid,  a  completely  transparent  residue  is  obtained, 
which  after  some  time  becomes  opaque.    These  salts  are  very  brittle, 
1  Monatsh.,  ix.,  157—164;  Jour.  Chem.  Soc,  1888,  846. 
