45  8  Examination  of  Lippia  Scaberrima.    { ^  oo^ober^SS™' 
ethyl  acetate,  and  the  solution  allowed  to  cool,  after  which  the 
crystalline  acid  which  had  separated  was  collected  on  a  filter.  These 
crystals  first  melted  at  530  C,  but  after  repeated  crystallization  from 
ethyl  acetate  the  melting  point  was  raised  to  740  C,  after  which  it 
remained  constant. 
0-1015  gave  0-2844  C02  and  01 176  H20.  0  =  76-4;  H  =  12-9, 
C20H40O2  requires  C  =  76  9;  H  =  12-8  per  cent. 
It  is  evident  that  this  substance  was  arachidic  acid. 
The  mother-liquors  from  this  arachidic  acid  were  concentrated, 
when  a  further  quantity  of  crystals  was  obtained.  This  was 
repeatedly  recrystallized  from  a  variety  of  solvents,  but  the  melting 
point  could  not  be  raised  above  540  C.  It  had  the  appearance  of  a 
mixture,  and  an  analysis  indicated  that  it  consisted  of  palmitic  and 
stearic  acids. 
The  original  filtrate  from  these  solid  acids  contained  a  consider- 
able quantity  of  an  oil,  which  was  found  to  be  a  mixture  consisting 
largely  of  unsaturated  acids.  It  was,  therefore,  converted  into  the 
lead  salts,  and  the  latter  treated  with  ether  and  filtered.  The 
ethereal  solution  thus  obtained  was  shaken  with  concentrated  hydro- 
chloric acid,  the  mixture  filtered,  and  the  separated  ethereal  liquid 
washed,  dried  and  evaporated.  The  unsaturated  acids  were  thus 
obtained  as  a  light  yellow  oil,  which,  on  distillation  under  15  mm. 
pressure,  passed  over  between  2250  and  245 0  C. 
00969  gave  0-2742  C02  and  o-iooi  H20.    C  =  77-2  ;  H  =  11*5* 
018H32O2  requires  C  =  77-1  ;  H  ==  1 1-4  per  cent. 
0-3270  absorbed  0-5215  iodine.     Iodine  value  ==  159-5. 
An  acid  of  the  formula  C18H3202,  containing  two  double  linkings, 
requires  an  iodine  value  of  181-4. 
From  these  results  it  is  evident  that  the  unsaturated  acids  con- 
sisted largely  of  linolic  acid,  or  of  an  acid  isomeric  with  the  latter. 
II.  Ether  Extract  of  the  Resins. 
The  portion  of  the  resins  soluble  in  ether  was  dark  green  in  color, 
and  amounted  to  54-5  grammes.  It  contained  a  small  quantity  of  a 
substance  which  was  only  very  sparingly  soluble  in  ether,  and  which, 
when  dissolved  in  warm  ethyl  acetate,  and  the  solution  cooled,  sepa- 
rated in  the  form  of  a  white,  amorphous  powder,  which  melted 
and  decomposed  at  210-2130  C. 
