28 
ON  THE  CHEMICAL  HISTORY  OF  LUPULIN. 
but  when  an  attempt  is  made  to  separate  it  from  the  tannic  pre- 
cipitate by  oxide  of  lead,  nothing  was  obtained  but  a  resinoid 
body.  The  tannic  precipitate,  as  well  as  the  solution  of  the  bit- 
ter principle,  was  treated  with  potassa  in  the  idea  of  obtaining 
a  volatile  alkali,  but  the  only  product  was  ammonia.  To  prove 
whether  this  ammonia  was  derived  from  the  decomposition  of  the 
bitter  principle  or  from  an  ammoniacal  salt  coexisting,  he  added 
an  alcoholic  solution  of  tartaric  acid  to  an  alcoholic  tincture  of 
lupulin  (1  to  4)  and  obtained  a  precipitate  of  bitartrate  of  am- 
monia. The  liquid  was  separated,  and  by  careful  evaporation 
it  yielded  resinous  matter  and  a  bitter  acid  liquid.  This  liquid 
was  digested  with  hydrated  carbonate  of  lead  and  evaporated  at 
a  low  temperature,  and  treated  with  alcohol  which  dissolved  the 
bitter  principle  and  left  the  tartrate  and  resinate  of  lead. 
The  aqueous  solution  of  this  body  is  precipitated  by  tannin, 
iodurettcd  iodide  of  potassium  chloride  of  gold  and  chloride  of 
platina,  which  affords  a  double  salt  soluble  in  alcohol.  This, 
submitted  to  heat  evolves  ammoniacal  vapors  and  an  odor  of 
burnt  horn.  Heated  wTith  potassa  it  gives  ammonia  and  a  resi- 
nous body.  When  an  attempt  is  made  to  evaporate  the  aqueous 
solution,  the  residue  consists  of  acetate  of  ammonia  and  resinous 
matter,  without  bitterness.  Being  unable  to  isolate  it,  or  to  get 
a  regular  combination  with  this  body  for  analysis,  the  author 
has  been  unable  to  demonstrate  its  true  nature,  yet  he  feels  jus- 
tified in  believing  that  this  extremely  unstable  bitter  principle  be- 
longs to  the  class  of  the  organic  alkalies. 
After  demonstrating  the  presence  of  free  phosphoric  acid  in 
the  decoction  of  lupulin  (which  he  believes  is  derived  from  phos- 
phate of  lime  by  the  reaction  of  valerianic  acid),  the  author  con- 
cludes his  second  essay  by  stating  that  the  cavity  of  the  grains 
of  lupulin  contains  an  abundant  resinous  matter  ;  an  essential 
oil  formed  of  a  hydro  carbon  with  the  formula  C10  H8 ;  and  an 
oxygenous  body  analogous  to  voter  ol  C12  H10  O2 ;  valerianic 
acid ;  a  nitrogenous  very  unstable  bitter  substance  (lupuline) 
possessing  some  of  the  properties  of  the  organic  alkalies  ;  an  am- 
moniacal salt ;  and  phosphate  of  lime. 
