436      Grindelia  Bobusta  and  Grindelia  Squarrosa.  {^^hll'tl'ms^^'^' 
Small  quantities  of  the  volatile  oils  were  obtained  by  distilling  each 
drug  with  water  and  shaking  the  distillate  with  petroleum  ether. 
The  oils  resemble  each  other  closely.  They  have  an  agreeable  aro- 
matic, pungent,  somewhat  mint-like  odor  and  burning  taste. 
II.  Treatment  with  Ether. 
The  petroleum  ether  remaining  in  the  drug  was  evaporated,  and 
the  drug  exhausted  with  successive  portions  of  ether.  Proportion 
extracted  by  this  solvent : — 
G.  robusta,     ....   4*02  per  cent.,  of  which  3'80  per  cent,  is  resin. 
G.  squarrosa,  ....    6-92      "  "  4-01 
The  resin  is  soft  (about  the  consistency  of  styrax),  of  a  greenish- 
black  color,  having  a  smooth  bland  taste  to  the  tongue,  but  after  a 
short  time  having  a  very  irritating  effect  on  the  fauces.  It  has  the 
odor  of  the  drug.  It  melts  at  about  40°  C.  On  the  addition  of 
sulphuric  acid  the  resin  dissolves  with  a  brown  color  and  a  rise  in 
temperature.  Nitric  acid  (sp.  gr.  1*42)  cold,  gives  a  yellow-green 
color ;  on  warming,  eifervescence  takes  place,  with  evolution  of  brown 
fumes  of  NO2  and  a  peculiar  smell. 
The  resin  dissolves  completely  in  a  weak  solution  of  the  caustic 
alkalies,  indicating  that  it  is  an  acid-resin.  On  neutralizing  the  resin 
with  caustic  alkali,  concentrating  and  allowing  to  stand,  prismatic 
crystals  were  obtained,  colorless,  with  a  cooling  saline  taste,  and 
insoluble  in  hot  and  cold  alcohol,  chloroform  and  ether.  A  portion  of 
the  resin  was  treated  with  20  per  cent,  alcohol,  the  residue  treated  with 
50  per  cent,  alcohol,  and  so  on  with  75  per  cent,  and  94  per  cent. 
75  per  cent,  alcohol  dissolved  the  larger  portion,  very  little  remain- 
ing ;  showing  that  a  75°  menstruum  would  exhaust  the  drugs  of 
their  resinous  constituents.  The  different  fractions  obtained  have  the 
same  melting  point  and  give  the  same  color-reactions  as  the  original  resin. 
A  portion  of  the  ethereal  extract  was  concentrated  and  precipitated 
in  distilled  water,  the  resin  collected,  dissolved  in  a  little  alcohol  and 
reprecipitated  in  water  containing  one  per  cent,  sulphuric  acid.  Each 
of  these  aqueous  solutions  of  the  ethereal  extract  were  treated  with 
petroleum  ether,  benzol,  chloroform  and  ether,  successively,  for 
alkaloids,  glucosides,  or  bitter  principles.  The  aqueous  solutions 
were  then  rendered  alkaline  and  again  agitated  with  the  same  solvents, 
with  negative  results  in  each  case,  except  that  the  chloroform  residue 
