EXAMINATION  OF  OIL  OF  PEPPERMINT.  107 
behaviour :  cedar,  no  change ;  fireweed,  slowly  golden  yellow, 
clear ;  Borton's,  pale  green,  clear  ;  spurious,  by  continued  boil- 
ing, light  brownish  yellow,  turbid,  soon  clear;  No.  7,  green 
reddish  brown,  turbid,  soon  clearing ;  No.  1  assumes  with  diffi- 
culty a  light  yellow  shade,  turbid  ;  the  others  remained  nearly 
colorless,  assuming  with  difficulty  a  scarcely  observable  brownish, 
greenish  or  yellowish  tint. 
It  will  appear  from  these  reactions  that  an  admixture  with 
turpentine  may  be  thought  probable,  and  as  I  had  occasion  to 
rectify  some  turpentine,  I  experimented  with  it.  It  was  per- 
fectly colorless,  and  almost  free  of  the  peculiar  penetrating 
odor  and  the  hot,  pungent  taste  of  the  common  oil;  it  dissolves 
in  8  parts  of  alcohol  at  60°,  with  l-10th  of  Borton's  peppermint 
in  7  parts,  with  2-10ths  in  3 h  parts,  and  the  solutions  remain 
clear  with  more  alcohol;  mixtures  with  from  3-10ths  to  9-10ths 
dissolve  in  f  or  J  part  of  alcohol,  and  the  solutions  are  turbid 
with  1J  p.  of  alcohol. 
The  reactions  of  a  mixture  of  5  p.  oil  of  turpentine  with  one 
of  peppermint,  when  brought  in  contact  with  iodine  at  60  and 
80°,  with  ethereal  solution  of  iodine  and  of  bromine,  and  when 
continually  boiled  with  nitroprusside  of  copper,  are  precisely  the 
same  as  those  of  the  fractions,  particularly  3  and  4. 
Fraction  No.  7  agrees  in  many  respects  with  Borton's  oil;  the 
principal  difference  is  their  solubility  in  alcohol.  As  I  have 
been  unable  to  produce  a  mixture  of  oil  of  peppermint  with  tur- 
pentine, cedar,  fireweed,  spearmint,  and  several  other  oils,  which 
would  dissolve  in  from  one  to  three  parts  of  alcohol,  and  more, 
I  was  at  one  time  inclined  to  suppose  the  spurious  oil  in  ques- 
tion to  be  the  oil  of  some  other  species  of  mint,  some  of  which 
have  a  resemblance  in  odor  with  peppermint.  This  supposition 
was  strengthened  on  finding  in  Darlington's  Flora  Cestrica,  page 
340,  the  following  sentence:  "This  species  (Mentha  canadensis 
&  acutifolia,  var.  borealis,)  is  not  so  pleasantly  aromatic  as  the 
preceding  (M.  piperita),  its  flavor  more  resembling  that  of 
Hedeoma  or  pennyroyal."  I  was  unable  to  obtain  any  further 
information  regarding  its  odor,  or  to  find  any  oil  of  this  plant. 
As  it  is  said  to  be  a  common  herb,  it  would  perhaps  be  well  for 
some  of  our  pharmaceutists  to  direct  their  attention  to  it,  with 
a  view  of  ascertaining  the  properties  of  its  oil,  and  whether  the 
plant  is  distilled  indiscriminately  with  peppermint. 
