486 
Oils  of  Peppermint  and  Spearmint. 
Am.  Jour,  rharm^ 
Oct.,  1885. 
tilling  4  ounces.  This  was  treated  and  distilled  3  times  with  sodium^ 
then  submitted  to  combustion  with  the  following  result : 
Carbon  84*08 
Hydrogen  1219 
Oxygen   3-73 
100-00 
As  this  contained  so  much  oxygen  it  was  allowed  to  stand  on  sodium, 
for  a  week.    The  light  portion  gave  on  combustion  : 
Carbon  83'96 
Hydrogen  12*28 
Oxygen   3-76 
100-00 
This  boiled  at  163°C.,  and  had  a  specific  gravity  of  '855  at  15°C_ 
Gladstone  eri  ves  1  /5°C  as  the  boiling  point  of  the  hydrocarbon  CjQHjgj^. 
and  the  specific  gravity  '8602  at  20°C.  He  does  not,  however,  give 
his  method  of  separation,  and  I  fail  to  find  that  anybody  has  ever 
separated  this  compound.  I  do  not  give  the  result  of  the  combustions 
as  evidence  that  there  is  no  hydrocarbon  present,  but  to  show  that  it 
exists  in  very  small  quantity,  and  that  it  is  isolated  with  extreme 
difficulty,  as  already  shown  when  the  light  portion  resulting  from  the 
distillation  of  120  pounds  of  the  oil,  rectified  twice  by  Mr.  Todd,  still 
contained  oxygen  after  prolonged  treatment  with  sodium.  Mr.  Todd 
states  as  his  opinion  that  the  amount  of  hydrocarbon  does  not  exceed  5 
per  cent.  It  is  probable  there  is  not  even  that  much  ]>resent.  It  is- 
well  known  that  a  very  small  proportion  of  the  hydrocarbon  will  pre- 
vent the  crystallization  of  the  pipuienthol. 
After  the  distillation  of  the  heavy  portion  of  the  oil,  there  remained 
a  resinous  mass  very  similar  to  that  obtained  from  spearmint  oil.  It 
is  probable  lhat  both  oils  contain  this  resin,  and  that  the  quantity  is 
increased  during  the  process  of  distillation.  This  view  is  the  result  of 
experiment,  as  well  as  of  a  statement  from  Mr.  Todd  that  the  distillate,, 
in  fractioning  the  oil,  increases  in  specific  gravity  until  the  middle  or 
latter  part  of  the  operation,  when  it  begins  to  decrease,  which  is  due,, 
no  doubt,  to  a  decomposition,  resulting  in  the  formation  of  the  resin. 
Summai'y. — 1.  The  oils  of  spearmint  and  peppermint  probably  con- 
tain hydrocarbons  which  are  identical. 
