420  Manufacture  of  Medicinal  Plasters.    {  sfpteXeVfiSa" 
realize  what  a  combat  with  difficulties  there  has  been  to  bring 
them  to  their  present  high  standard.  Probably  no  other  branch 
of  the  pharmaceutical  art  has  been  the  occasion  of  so  much  toil, 
anxiety,  and  discouragement  before  any  measure  of  success  was 
met  in  a  pharmaceutical,  commercial,  or  therapeutic  sense.  The 
evolution  of  India  rubber  plaster  making  has  now  reached  a  point 
where  it  not  only  requires  a  large  amount  of  machinery,  but  a 
vast  amount  of  detail  in  every  step,  which  only  long  experience  and 
accurate  judgment  can  give.  Prominent  among  the  names  con- 
nected with  plaster  making  are  those  of  Dr.  Grovenor,  of  Boston, 
Mass.,  the  late  George  J.  Seabury,  and  the  late  Robert  W.  Johnson, 
of  Johnson  &  Johnson,  New  Brunswick,  N.  J.  It  is  to  these  men 
that  w7e  are  indebted  for  the  idea  of  making  pharmaceutical 
plasters  with  a  rubber  base  and  for  the  great  benefits  which  have 
accrued  to  medicine  and  surgery  through  the  improvement  in  the 
art. 
These  manufacturers  first  used  what  is  known  as  the  benzin 
process.  After  considerable  struggling  they  found  that  many  of 
the  medicaments  of  the  Pharmacopoeia  were  not  compatible  with 
rubber  dissolved  in  a  solvent,  and  the  products  were  not  fitted  for 
therapeutic  use  and  were  worthless  commercially.  Benzin  plasters 
are  still  made,  but  they  rapidly  decompose  and  many  pharmacopceial 
drugs  are  useless  in  such  a  combination. 
The  pioneers  in  India  rubber  plaster  making  found  that 
mechanical  troubles  were  not  all  that  were  to  be  overcome,  and  it 
was  only  after  a  long  struggle  that  the  point  was  reached  where 
the  required  pharmaceutical  combination  could  be  made  and 
marketed  in  the  shape  of  India  rubber  plasters,  and  it  was  not 
until  a  few  years  ago  that  it  was  recognized  that  a  plaster  was 
valueless  to  medicine  and  pharmacy  if  only  the  mechanical  perfection 
was  considered,  without  regard  to  the  therapeutic  efficiency  and 
certain  other  requirements.  It  wras,  therefore,  determined  that 
mechanically  the  plasters  should  be  made  perfect  and  above  all  that 
the  medication  should  be  absorbed  by  the  integument  and  thus 
make  the  plaster  not  only  a  mechanical  application,  but  a  therapeutic 
agent. 
These  conditions  have  not  yet  been  completely  fulfilled.  It  is 
undoubtedly  true  that  rubber  base  plasters  are  superior  as  thera- 
peutic agents  to  those  made  with  a  resin  or  diachylon  base,  and 
the  rubber  base  plasters  have  been  improved  in  such  a  way  as  to 
