Am.  Jour.  PruRM.  \ 
April  ],  1871.  j 
Use  of  Liquid  Caoutchouc,  etc. 
153 
iilkaloid  nor  an  acid  principle,  being  entirely  indifferent  to  the 
vilkalies  and  not  reddening  litmus  paper.  The  therapeutic  properties 
of  this  substance  have  not  been  ascertained. 
ON  THE  USfi:  OF  LIQUID  CAOUTCHOUC  AS  AN  ADDITION  TO 
EMP.  BELLADONNA]  AND  OTHER  PLASTERS. 
By  J.   WiLLITTS  WORTHINGTON. 
The  author  has  treated  this  subject  at  some  length  in  his  Inaugural 
Essay  before  the  Philada.  College  of  Pliarmacy,  from  which  we  ab- 
stract the  following  : 
Much  difficulty  has  been  experienced  by  pharmaceutists  in  prepar- 
ing belladonna  plaster  so  as  to  retain  its  adhesiveness  when  kept 
ready  spread  for  some  time.  The  proposed  improvement  consists  in 
ihe  addition  of  India  rubber  used  in  the  form  of  a  solution,  made  as 
follows  : 
'  Take  of  pure  Caoutchouc,  cut  in  small  pieces,       an  ounce. 
Benzine  (from  Petroleum),  a  pint. 
Macerate  with  occasional  agitation  in  a  suitable  stopped,  wide, 
•mouthed  bottle  until  a  thick,  saturated  solution  is  obtained.  To 
prove  its  efficacy  in  preserving  the  pliability  of  plasters,  the  author 
prepared  a  mixture  of  8  ounces  of  Burgundy  pitch,  4  drams  of  yellow 
wax,  2  drams  of  rosin  and  2  drams  of  lard.  Melted  and  strained. 
This,  when  spread  and  kept  two  months,  became  very  brittle  and 
cracked  on  handling. 
The  same  ingredients,  witli  the  addition  of  4  drams  of  liquid  caout- 
chouc incorporated  when  they  were  in  a  fused  state,  possessed  the 
following  characters  : 
Very  little  tendency  to  crack,  retains  its  pliability,  is  more 
adhesive,  and  has  a  beautiful,  smooth,  glossy  appearance.  After  two 
months,  part  of  it  very  cold  weather,  this  plaster  retained  its  plia- 
bility. 
•  Experiments  were  then  made  with  officinal  belladonna  plaster, 
which  resulted  in  the  following  proportion  being  considered  most 
suitable  : 
Take  of  Belladonna  plaster  (U.  S.  P.),        seven  drams. 
Liquid  Gum  Elastic,  one  dram. 
The  belladonna  plaster  to  be  melted  by  a  water-bath,  and  the 
liquid  rubber  then  added  and  stirred  well  until  united  thoroughly. 
