426  Manufacture  of  Medicinal  Plasters.    { ^pt/mbel- *m.o. 
the  amount  now  prescribed  as  the  standard.  The  result  was  not 
only  confusing,  but  in  certain  instances  serious  consequences  arose 
therefrom.  The  eighth  revision  of  the  Pharmacopoeia  established 
the  standard  of  0.38  to  0.42  per  cent,  alkaloid.  The  British  Phar- 
macopoeia of  1880  had  no  definite  alkaloidal  standard  for  this 
plaster,  but  the  British  Pharmacopoeia  of  1898  prescribed  that  bel- 
ladonna plaster  should  contain  0.5  per  cent,  of  the  alkaloid  of 
belladonna  root. 
It  is  the  opinion  of  many  authorities  that  both  of  these  standards 
are  high.  Numerous  instances  have  arisen  whereby  the  constitu- 
tional effects  of  belladonna  have  been  produced  by  the  application 
of  belladonna  plasters.  The  Pharmaceutical  Society  of  Great 
Britain  has  promulgated  a  formula  for  a  milder  belladonna  plaster 
standardized  to  0.25  per  cent,  alkaloid,  giving  as  a  reason  therefor 
that  a  plaster  of  such  a  strength  was  less  likely  to  produce  poisonous 
symptoms  than  that  made  in  accordance  with  the  British  Pharma- 
copoeia. 
My  suggestion  would  be  that  the  standard  strength  for  bella- 
donna plasters  should  be  0.3  per  cent,  of  the  alkaloids  of  belladonna. 
In  addition  to  the  plasters  of  the  Pharmacopoeia,  we  find  a 
number  of  kinds  in  the  National  Formulary.  In  the  third  edition 
of  this  book  we  have  aromatic  or  spice  plaster — a  combination  of 
cloves,  cinnamon,  ginger,  capsicum,  and  camphor,  with  cottonseed 
oil  and  lead  plaster  as  a  base;  camphorated  brown  plaster,  which 
resembles  the  camphorated  mother's  plaster  of  the  German 
Pharmacopoeia,  and  is  made  up  of  red  oxide  of  lead,  olive  oil,  and 
camphor;  compound  tar  plaster,  which  is  composed  of  tar,  podo- 
phyllum, and  poke  root  combined  with  resin.  These  last  two 
plasters  are  of  the  nature  of  the  old  time  sticking  salves,  scarcely 
resembling  the  modern  conception  of  a  plaster. 
In  the  addenda  to  the  National  Formulary  we  have  ammoniac 
plaster,  which  is  made  up  entirely  of  gum  ammoniac;  ammoniac 
and  mercury  plaster,  consisting  of  gum  ammoniac  and  oleate  of 
mercury  combined  with  a  lead  plaster  base ;  arnica  plaster,  which 
is  prepared  with  the  extract  of  arnica  root  combined  with  resin 
plaster;  asafetida  plaster,  a  combination  of  asafetida,  lead  plaster, 
galbanum,  and  yellow  wax;  strengthening  plaster,  consisting  of 
ferric  hydroxide  combined  with  olive  oil,  burgundy  pitch,  and  lead 
plaster  ;  burgundy  pitch  plaster,  a  combination  of  burgundy  pitch, 
olive  oil,  and  yellow  wax ;   Canadian  pitch  plaster,  consisting  of 
