202 
EMPLASTRUM  EXTRACTI  ACONITI  RADICIS. 
In  its  character  the  stearoptene  partakes  of  the  nature  of  true 
camphor.  Both  are  formed  by  the  addition  of  oxygen  to  a 
carbo-hydrogen  radical.  The  formula  of  the  oily  base  of  cam- 
phor is  C20  H16.  With  02  it  forms  camphor  C20  H16,  02  =  2CJ0 
H8,  0 ;  while  oil  of  monarda  is  a  tribasic  oxide  of  the  radical 
C10  H7,  which  by  the  absorption  of  02  is  wholly  converted  into 
three  equivalents  of  monarda  camphor,  thus  :  3C10  H7,  0-t-02  = 
3C10  H7  0,  a  formula  differing  from  that  of  camphor  in  contain- 
ing two  equivalents  less  of  hydrogen. 
If  to  monarda  camphor  we  could  add  two  equivalents  more  of 
oxygen,  we  should  have  the  formula  of  anhydrous  camphoric 
acid,  C10  H7  03.  But  when  we  attempt  to  oxidize  monarda 
camphor,  the  oxygen  displaces  a  part  of  its  hydrogen,  forming 
water,  and  converts  it  into  a  resinous  matter,  which,  as  I  have 
said  before,  upon  being  further  treated  with  nitric  acid,  is  trans- 
formed into  oxalic  and  carbonic  acids  and  water.  The  formation 
of  oxalic  acid  in  this  case  is  of  some  interest,  as  essential  oils, 
and  particularly  those  of  a  terebinthinate  nature,  are  converted 
by  nitric  acid  into  resins,  peculiar  acids  and  carbonaceous  pro- 
ducts, but  yield  no  oxalic  acid. 
Philadetyliia,  Jan.  13th,  1853. 
EMPLASTRUM  EXTRACTI  ACONITI  RADICIS. 
By  Wiliam  Procter,  Jr. 
Having  been  requested  by  Dr.  Francis  Gurney  Smith  to  prepare 
a  plaster  medicated  with  aconitia,  the  following  formula  was  sug- 
gested by  me  as  being  less  expensive  than  one  requiring  the  pure 
alkaloid,  yet  possessed  of  equal,  if  not  superior  efficiency,  be- 
cause the  greater  bulk  of  the  extract  would  prevent  the  plaster 
from  masking  the  power  of  the  active  ingredient,   and  its  ready 
solubility  more  favorable  to  the  influence  of  the  remedy. 
Take  of  Aconite  root,  in  coarse  powder,  four  ounces. 
"       Alcohol,  sp.  gr.  835,  a  sufficient  quantity. 
"       Adhesive  plaster,  three  ounces  and  a  half. 
Moisten  the  powdered  aconite  root  with  six  ounces  of  alcohol, 
and  permit  it  to  macerate  twenty-four  hours,  then  put  it  in  a  small 
displacer,  and  when  properly  packed,  pour  on  gradually  sufficient 
