302 
ON  THE  RESINOIDS. 
•what  turbid,  of  a  brown  color ;  two  fluid  ounces  of  aqua  ammonia 
being  thrown  in,  rendered  it  perfectly  limpid,  presently  pro- 
duced a  crystalline  earthy  precipitate,  which,  when  dry,  weighed 
78  grains.  The  clear  liquor  was  then  evaporated  to  one-fourth 
of  its  original  bulk.  The  free  ammonia  had  of  course  escaped. 
On  cooling,  a  pellicle  formed  on  the  surface,  and  a  semi-crystal- 
line flakey  matter  was  deposited,  copiously  enveloped  in  a  gelatin- 
ous mass.  In  order  to  separate  the  semi-crystalline  matter 
he  diluted  the  whole  with  cold  water,  and  decanted  off  the  clear 
liquor,which  conveyed  away  with  it  most  of  the  gelatinous  mass. 
That  which  remained  was  nearly  dried,  and  treated  with  alcohol  of 
sp.  gr.  -825.  The  solution  thus  obtained  was  filtered  and  eva- 
porated by  a  water  bath,  depositing,  towards  the  end  of  the  pro- 
cess, the  original  semi-crystalline  substance  in  the  form  of  a 
brownish  yellow  granular  mass.  Suspecting  that  it  was  not  yet 
in  a  state  of  purity,  and  having  observed  its  sparing  solubility 
in  cold  water,  I  subjected  it  to  a  boiling  heat  in  distilled  water  ; 
when  it  entirely  dissolved,  except  a  slight  portion  of  impurity.  As 
soon  as  the  solution  was  allowed  to  cool  this  substance  separated 
in  extremely  small  flocculent  crystals,  slightly  heavier  than  the 
water.  In  order  to  prove  its  supposed  cathartic  effect,  half  a 
grain  was  taken,  and  after  the  lapse  of  a  reasonable  length  of 
time,  it  produced  a  mild  cathartic  effect,  which  convinced  me 
that  the  bitter  principle  obtained  by  Mr.  Hodgson  proved  to  be 
a  cathartic,  having  a  slight  drastic  effect.  When  dry,  this  sub- 
stance, after  being  purified,  was  obtained  in  beautiful  straw 
colored  scales  of  considerable  brilliancy,  easily  pulverizable, 
slightly  deliquescent  in  the  air,  and  having  a  strong  bitter  taste, 
very  permanent,  but  not  at  first  apparent,  owing  probably  to  its 
difficult  solubility,  as  the  alcoholic  solution  is  excessively  bitter  ; 
soluble  in  strong  alcohol ;  slightly  in  cold,  and  much  more  in 
boiling  water  ;  slightly  soluble  in  sulphuric  ether.  When  dry 
it  has  but  little  odor,  the  solutions*having  a  peculiar  smell,  some- 
what resembling  that  of  the  root  ;  with  sulphuric  acid,  an  olive 
green  color  passing  afterwards  to  a  purple ;  exposed  to  heat 
alone,  it  fuses,  blackens,  and  dissipates  in  a  dense  smoke. 
The  most  important  of  these  active  principles  possess  in  general 
the  properties  of  the  common  resins,  viz.  fusibility,  inflammabil- 
ity, solubility  in  alcohol  and  not  in  water,  etc.  ;  but  as  they  are 
