108  EXAMINATION  OF  OIL  OF  PEPPERMINT. 
Zeller  requires  good  oil  of  peppermint  to  be  soluble  in  be- 
tween one  and  three  parts  of  alcohol  of  »85,  and  to  become  turbid 
with  more.  I  have  not  met  with  any  great  difficulties  to  procure 
oil  of  that  behaviour  towards  alcohol  of  '83.5.  The  New  Jersey 
oil  mentioned  above,  however,  dissolved  in  i  p.  alcohol  and  re- 
mained clear  with  60  p.  c.  more  ;  it  dissolved  iodine  only  by  con- 
tinued agitation,  produced  with  ethereal  bromine  a  green,  spread- 
ing, scarcely  thickening  liquid,  and  was  rendered  yellow  by 
nitroprusside  of  copper.  I  supposed  this  to  be  an  adulterated 
oil ;  but  since,  I  have  obtained  two  specimens  of  Borton's  oil, 
which,  though  agreeing  in  every  other  respect  with  the  reac- 
tions of  the  above  sample  of  his  make,  are  dissolved  by  \  and  \ 
parts  of  alcohol  without  being  rendered  turbid  by  more.  Though 
crude  oils,  their  flavor  appears  to  be  a  pure  peppermint,  and  the 
question  now  arises,  What  influence  has  the  soil,  the  maturity, 
and  the  age  of  the  herb  on  the  solubility  of  the  oil  obtained  from 
it  ?  I  consider  it  an  important  question,  and  probably  some  one 
who  has  access  to  peppermint  plantations  will  take  it  up  for  the 
common  benefit  of  all. 
As  the  matter  now  stands,  it  seems  to  me  that  Zeller's  test 
with  alcohol  cannot  be  relied  on  for  all  oil  of  peppermint.  Bor- 
ton's first  specimen,  when  in  excess  in  a  mixture  with  oil  of  fire- 
weed,  dissolved  in  from  A  to  1  part  of  alcohol  and  become  turbid 
by  from  1|  to  1|  parts ;  with  the  fire  weed  in  excess,  it  required 
more  alcohol  for  solution,  but  even  an  admixture  of  «2  of  pep- 
permint, rendered  the  solution  slightly  cloudy  though  not  milky. 
On  the  other  hand,  to  the  last  mentioned  specimen  of  Borton's 
and  the  New  Jersey  oil,  the  property  of  dissolving  in,  and  be- 
coming turbid  with,  more  alcohol,  may  be  imparted  by  oil  of  red 
cedar;  a  mixture  containing  only  «3  of  the  latter,  dissolved  in  J, 
and  was  slightly  turbid,  with  3|  p.  c.  alcohol.  But  such  mixtures 
were  not  changed  in  color  by  nitroprusside  of  copper,  unless  the 
boiling  was  continued  for  some  time. 
For  the  strength  of  the  test  liquids  and  the  manner  of  apply- 
ing the  various  reagents,  I  have  to  refer  the  reader  to  my  papers 
in  the  Proceedings  of  the  Amer.  Pharm.  Ass.,  for  1858  and 
1859.  The  reactions  of  my  rectified  oil  of  turpentine  were 
identical  with  those  published  in  the  Proceedings  for  1859, 
page  345. 
