Am'jJn°iyri9osarm'}    Improved  Acetone  Cantharidal  Collodion.  341 
and  the  British  Pharmaceutical  Codex1  states  its  solubility  in  acetone 
as  1  in  40,  in  chloroform  1  in  65,  in  acetic  ether  1  in  150,  in  ether  1 
in  700,  and  still  more  sparingly  in  alcohol.  Many  of  the  statements 
of  the  authorities  concerning  the  solubility  of  this  principle  are, 
however,  discordant  and  the  subject  is  in  need  of  further  critical 
study. 
The  writer2  has  elsewhere  called  attention  to  the  peculiar  and 
valuable  solvent  properties  of  acetone  and  its  remarkable  miscibility 
with  other  solvents  as  well  as  with  water.  Since  that  time  it  has 
been  officially  recognized  and  directed  in  the  preparation  of  some 
of  the  oleoresins  and  its  application  in  numerous  manufactures  has 
made  it  an  article  of  considerable  commercial  importance,  and  sup- 
plies of  pure  acetone,  suitable  for  pharmaceutical  purposes,  are  now 
available  at  moderate  prices. 
More  recently 3  he  proposed  its  use  as  a  substitute  for  ether  in  the 
preparation  of  collodions.  In  the  latter  communication  a  formula 
was  given  for  an  acetone  cantharidal  collodion,  and  the  object  of 
this  note  is  to  publish  the  results  of  more  recent  study  and  submit 
the  following  improved  formula  : 
ACETONE  CANTHARIDAI,  COI^ODION. 
Take  of  Cantharides  in  fine  powder  60  grammes 
Glacial  acetic  acid  -.   5  c.c. 
Pyroxylin   4  grammes 
Camphor   1  gramme 
Acetone  sufficient  quantity  to  make  100  grammes 
Mix  the  glacial  acetic  acid  with  55.  c.c.  of  acetone  and  moisten 
the  powdered  cantharides  with  this  mixture  and  set  it  aside  in  a 
closely  covered  container  for  twenty-four  hours.  Then  pack  in  a 
cylindrical  percolator  and  slowlydisplace  with  acetone  until  exhausted. 
Reduce  the  percolate  by  distillation  on  a  water-bath  to  95  grammes, 
and  when  cold  dissolve  in  this  the  pyroxylin  and  camphor.  If  neces- 
sary, make  up  weight  with  acetone  to  100  grammes. 
If  the  rate  of  percolation  is  rapid,  from  125  to  150  grammes  of 
percolate  will  be  obtained  befor  the  drug  is  exhausted,  but  by  care- 
fully regulating  the  flow  the  cantharides  will  be  practically  exhausted 
when  95  grammes  of  percolate  is  secured. 
1  Br.  Ph.  C,  204. 
2  Amer.  Jour,  of  Pharmacy,  1892,  p.  146. 
3  Proceedings  A.  Ph.  A.,  1906,  p.  502. 
