144  Isolation  of  a  Substance  from  Sesame  Oil.{Am£T^^m* 
in  benzine,  turpentine,  carbon  disulphide,  and,  of  co.urse,  alcohol  and 
glacial  acetic  acid,  very  soluble  in  chloroform,  insoluble  in  water  and 
alkalies  and  also  hydrochloric  acid,  and  decomposed  by  sulphuric 
and  nitric  acids.  It  was  quite  neutral  to  litmus  and  other  indicators. 
It  gave  no  reaction  with  HC1  solution  of  pyrogallol,  proving  that  it 
was  not  the  cause  of  the  purple  color  which  formed  the  base  of 
the  new  test.  Nitro-sulphuric  acid,  however,  gave  a  green  and  then 
bright  red  color,  similar  to  that  obtained  on  treating  the  gelatinous 
extract  with  the  same  reagent,  and  corresponding  to  the  U.S  P.  test 
for  sesame  oil.  On  treating  the  alkaline  liquor  from  which  the 
substance  had  deposited  with  HC1  solution  of  pyrogallol,  the  purple 
color  was  at  once  obtained.  The  new  substance  may  therefore  be 
considered  as  the  cause  of  the  color  described  in  the  U.S. P.,  but 
not  of  pyrogallol  coloration.  The  gelatinous  extract  would  appear 
from  the  foregoing  to  be  a  mixture  of  substances  and  not  a  simple 
resinoid  body,  as  one  would  infer  from  the  "  Pharmacographia."  In 
fact,  the  great  proportion  of  the  extract  is  simply  oil,  the  substance 
which  I  have  been  able  to  separate  forming  a  very  small  proportion, 
indeed. 
The  following  is  a  comparison  in  a  tabulated  form  between  the 
properties  of  the  new  substance  and  those  of  oleic  acid  : 
With  nitro-sulphuric  acid  :  New  substance  green,  then  bright  red  ;  oleic  acid, 
brownish. 
With  nitric  acid  :  New  substance,  green,  then  yellow. 
With  pyrogallol  solution  :  New  substance,  no  reaction  ;  oleic  acid,  faint  red. 
With  sugar  and  sulphuric  acid  :  New  substance,  brownish  ;  oleic  acid,  brown, 
afterwards  bright  violet. 
Neither  stearic,  palmitic  or  myristic  acids  gave  any  definite  color 
with  the  foregoing  reagents.  It  will  be  observed  that  oleic  acid  is 
mentioned  as  giving  a  violet  color  with  sulphuric  acid  and  sugar, 
which  fact  I  have  not  yet  seen  stated.  It  is  very  charcteristic  of 
oleic  acid. 
With  the  collection  of  facts  I  have  here  recorded,  I  now  turned 
my  attention  to  what  the  percentage  composition,  and  from  that  the 
formula,  of  the  substance  might  be.  I  therefore  proceeded  to  pre- 
pare more  of  the  substance,  in  order  to  perform  a  combustion.  Halt 
a  gallon  of  the  oil  was  used  in  the  extraction  of  the  substance  and 
from  that  I  obtained  a  yield  of  crystals  equivalent  to  -04  per  cent. 
The  method  employed  was  that  formerly  described,  and  I  may 
