32  Standard  for  Belladonna  Plaster.  {A^a^rryfSm' 
Cl0H16,  which  belongs  to  the  "aliphatic  terpene "  class.  These 
bodies  are  highly  interesting,  but  so  far  have  not  been  completely 
investigated.  They  are  hydrocarbons  with  an  open  chain  of  carbon 
atoms  containing  three  double  bonds,  and  are  characterized  by  a 
low  specific  gravity,  high  refractive  power  (compared  with  ordinary 
terpenes)  and  excessive  tendency  to  polymerize.  This  peculiarity 
renders  their  investigation  very  difficult.  It  is  not  unlikely  that 
they  form  the  mother  substance  of  quite  a  number  of  other  con- 
stituents of  essential  oils.  In  the  highest  boiling  parts  of  sassafras 
leaf  oil  some  cadinene  seems  to  be  present,  and  also  a  paraffin-like 
substance  melting  at  5 8°  C.  Such  paraffines  are  often  found  in  oils 
distilled  from  leaves,  as  in  oil  of  Gaultheria  and  otto  of  roses ;  the 
latter  contains  so  large  an  amount  that  the  paraffines  crystallize  out 
at  even  a  moderate  temperature. 
Reviewing  this  enumeration  of  the  chemical  constituents  of  the 
two  oils  from  sassafras,  we  find  therein  a  striking  and  interesting 
example  of  the  ability  of  some  plants  to  produce,  in  their  various 
parts,  oils  which  are  fundamentally  different  in  their  chemical  com- 
position. It  would  be  very  desirable  if  extended  researches  in  this 
direction  could  be  made  with  other  aromatic  plants,  as  such  investi- 
gations would  probably  throw  some  light  upon  the  question  which 
so  far  has  been  found  unanswerable :  How  does  the  plant  produce 
the  great  variety  of  complicated  substances,  the  mixture  of  which 
constitutes  its  essential  oils  ? 
THE  PHARMACOPGEIAL  STANDARD  FOR  BELLADONNA 
PLASTER. 
By  Carx  E.  Smith. 
In  a  recently  issued  pamphlet  published  by  Johnson  &  Johnson, 
entitled  "  Red  Cross  Notes,"  an  article  appeared  treating  of  Bella- 
donna Plasters,  in  which  was  discussed,  among  other  matters,  a 
paper  contributed  by  the  writer  to  the  April  number  of  the  Ameri- 
can Journal  of  Pharmacy,  representing  a  report  on  analyses  of 
commercial  belladonna  plasters,  made  under  the  auspices  of 
Research  Committee  D.,  Section  II.,  of  the  Committee  of  Revision 
of  the  U.  S.  Pharmacopoeia. 
The  statement  is  made  in  this  pamphlet,  that  in  an  attempt  to 
establish  a  standard  for  belladonna  plasters  an  error  was  made  by  the 
