QN  THE  CONSTITUTION  OF  SCAMMONY  RESIN.  431 
acetate  of  copper,  acetate  and  subacetate  of  lead,  nitrate 
of  silver  and  sesquichloride  of  iron  (difference  from  guaia- 
cum.)  An  adulteration  with  the  resin  of  jalap  (Ipomoea 
jalapa,  Nutt.)  is  detected  by  the  almost  insolubility  of  the  lat- 
ter in  ether.  As  an  average  from  8  analyses,  the  author  obtained 
C56.50,  H7-97,  035.53,  agreeing  well  with  Keller's  results,  but 
more  so  with  Mayer's  analyses  of  Jalapin,  the  resin  from  Con- 
volvulus orizabensis,  Pell.  The  formula  CggH^gOg^  requires 
56-66,  7.77  and  35-57  per  cent. 
The  resin  was  dissolved  in  caustic  baryta,  the  latter  precipi- 
tated by  sulphuric  acid,  an  excess  of  it  removed  by  hydrated 
oxide  of  lead,  and  the  lead  thrown  down  by  sulphuretted  hydro- 
gen. The  colorless  acid  liquid  possesses  a  peculiar  odor,  which 
is  entirely  removed  by  distilling  it  to  a  syrupy  residue,  after  re- 
newing the  water  several  times.  The  distillate  was  turbid,  of  a 
strong  acid  reaction,  and  yielded,  after  being  evaporated  with 
carbonate  of  soda,  on  distilling  with  phosphoric  acid,  a  small 
quantity  of  a  volatile  acid,  resembling  butyric  and  valerianic 
acid  in  odor.  This  impurity  of  the  resin  was  not  further  ex- 
amined. From  the  residue  in  the  retort  a  crystalline  mass  is 
separated,  apparently  identical  with  one  of  the  products  of  de- 
composition by  acids.  Merely  traces  of  this  crystalline  princi- 
ple and  volatile  acid  are  obtained  from  pure  resin. 
The  syrupy  residue  is  treated,  when  necessary,  with  animal 
charcoal,  and  evaporated  to  dryness,  when  an  amorphous  yel- 
lowish mass  remains,  resembling  the  original  resin.  It  is  very 
deliquescent,  inodorous,  of  an  acrid,  acidulous,  afterwards  bit- 
terish taste,  free  from  sugar,  and  soluble  in  alcohol,  water,  and 
less  in  ether.  This  scammonic  acid  gave  from  4  analyses 
C54-59,H8'16, 037-25,  corresponding  with  Mayer's  jalapic  acid, 
for  which  he  calculated  CggH5(.032,3HO.  Fused  with  an  excess 
of  baryta,  or  dissolved  in  baryta  water,  and  the  excess  removed 
by  carbonic  acid,  the  amorphous  mass  obtained  has  the  composi- 
tion  3BaO,  CeaH^A^- 
If  scammonic  acid  is  heated  with  dilute  sulphuric  acid,  or  if 
the  hot  solution  of  the  resin  in  baryta  water  is  mixed  with  an 
excess  of  strong  hydrochloric  acid,  oily  drops  were  separated, 
which,  after  congealing,  were  purified  by  recrystallization  from 
ether  or  diluted  alcohol.    The  filtrate  from  this  crystalline  body 
