200  Unnas  Medicated  Skin  Varnishes.  {^m-i^\\\l^m' 
half  an  hour  on  the  steam-bath.  The  salep  basis  contains  less  bas- 
sorin  but  more  starch. 
Casein  Varnish. — The  casein  obtained  by  coagulating  skim-milk 
with  rennet  at  a  temperature  of  35 °  to  400,  is  washed  and  dried 
until  it  forms  a  yellowish-white  sandy  powder  soluble  in  alkaline 
solutions.  In  preparing  the  casein  varnish  this  casein  is  dissolved 
by  means  of  borax.  For  20  parts  casein,  2-5  parts  of  borax  and 
77  5  parts  water  furnish  a  rapidly  drying  uniform  covering  mateiial. 
The  alkaline  characters  of  the  borax  are  marked  by  the  casein. 
Admixtures  of  heavy  pulverulent  substances  readily  settle  out  of 
this  basis  and  it  is  requisite  to  distribute  them  by  shaking.  A 
varnish  of  casein  and  glycerin  is  prepared  by  dissolving  the  casein 
in  3  or  3  5  parts  of  ammonia,  adding  a  quantity  of  glycerin  equal 
in  weight  to  the  casein,  and  heating  to  drive  off  the  ammonia.  The 
resulting  mass  mixed  with  twice  its  weight  of  boiling  water  gives 
an  excellent  permanent  emulsion. 
Amber  Varnish  is  made  by  dissolving  a  mixture  of  amber  and 
turpentine  in  alcohol.  It  must  not  be  used  as  a  vehicle  for  the 
application  of  zinc  oxide. 
Castor  Oil  and  Shellac  Varnish. — With  1  part  shellac,  i  part 
castor  oil,  and  3  parts  alcohol,  a  varnish  is  obtained  which  forms  a 
good  flexible  covering  easily  removed  by  alcohol. 
Ca?iada  Balsam  and  Collodion  Varnish. — Sixteen  parts  collodion 
with  1  part  Canada  balsam  gives  a  material  suitable  for  the  appli- 
cation of  pyrogallol,  and  it  can  be  easily  removed  by  alcohol. 
Castor  Oil  and  Collodion  Varnish  — Eight  parts  collodion  and  1 
part  castor  oil. 
Lead  Ricinoleate  Varnish. — One  part  lead  oxide  heated  with  1  5 
part  castor  oil  to  saponification  and  mixed  with  2  parts  absolute 
alcohol,  gives  a  good  skin  varnish. 
Chrysarobin  Amber  Varnish. — One  part  chrysarobin  and  20  parts 
of  amber  dissolved  in  turpentine. 
Pyrogallol  Shellac  Varnish. — One  part  pyrogallol,  1  part  castor- 
oil,  5  parts  shellac  and  15  parts  absolute  alcohol. 
Salicylic  Acid,  Canada  Balsam,  and  Collodion  Varnish. — One  part 
Canada  balsam,  10  parts  collodion  and  3  parts  salicylic  acid. 
Zinc  Oxide,  Castor  Oil,  and  Collodion  Varnish. — Two  parts  zinc 
oxide,  2  parts  castor  oil  and  16  parts  collodion. 
Zinc  and  Lead  Ricinoleate  Varnish. — Five  parts  lead  ricinoleate, 
