174 
Quinium  Salts. 
i  Am.  Jour.Pharm. 
1     April,  1883. 
the  fact  that  no  recognized  and  definite  standard,  for  comparison  exists. 
The  bitterness  of  the  substance  of  course  diminishes  in  proportion  to 
the  deficiency  of  quinine  contained  in  it,  and  the  degree  of  its  envelop- 
ment by  the  inert  acid  tannolate  that  is  superadded.  When  quinine 
and  tannin  are  mixed  in  equivalent  proportion,  that  is,  one  m.  of 
each,  a  tannolate  is  formed,  but  tannin  remains  in  excess.  When  qui- 
nium sulphate,  tannin  and  hydrosodic  carbonate  are  mixed  in  equiva- 
lent proportion  a  tannolate  is  also  formed,  but  tannin  remains  in  excess 
as  before.  It  seems,  therefore,  that  tannin  combines  with  quinine  in  a 
smaller  proportion  than  one  m.  of  each.  The  yield  from  872  parts  of 
quinium  sulphate  is  1,160  parts.  Tannin,  as  already  stated,  has  a  great 
affinity  for  neutral  salts.  It  unites  with  them  directly,  unattended 
by  decomposition.  When,  for  instance,  tannin  and  potassic  acetate  are 
mixed,  a  voluminous  buff-colored  precipitate  is  immediately  formed. 
On  warming  the  mixture  the  precipitate  gradually  dissolves  completely, 
but  whilst  this  is  taking  place  a  portion  of  it  agglutinates  to  a  brown- 
green  resinous  mass.  If  the  heat  is  now  discontinued,  the  dissolved 
portion  again  gradually  precipitates.  By  stirring  this  it  also  becomes 
adherent,  but  its  color  is  now  light-brown.  Other  portions  of  lighter 
and  lighter  tints  may  thus  be  successively  obtained.  Various  other  salts 
may  likewise  be  produced  of  different  shades  with  appropriate  modifi- 
cations of  this  method.  The  results  show  that  the  colored  impurity  of 
tannin  attaches  itself  chiefly  to  the  first  formed  parts  of  the  precipi- 
tates. These  secondary  tannolates  also  have  a  powerful  attraction  for 
each  other.  For  example,  if  quinium  chloride  is  mixed  with  tannin 
in  the  proportion  of  their  equivalents,  namely,  414*5  and  322  parts 
respectively,  a  greenish-yellow  tannolate  is  generated,  but  tannin  re- 
mains largely  in  excess.  But  by  adding  in  conjunction  one  m.  of 
potassic  acetate,  98  parts,  the  tannin  is  all  absorbed  into  the  resulting 
-compound,  but  quinium  chloride  now  remains  in  excess.  The  product 
in  this  case  is  in  the  proportion  of  610  parts.  Yet  when  two  ms.  of 
quinine  chloride  and  one  m.  each  of  tannin  and  potassic  acetate  are 
used  the  yield  is  780  parts,  whilst  the  quinium  chloride  is  again  greatly 
in  excess.  It  appears,  therefore,  that  in  this  instance  the  acetate  deter- 
mines the  absorption  of  all  the  tannin,  at  the  same  time  taking  pre- 
cedence over  the  quinium  salt. 
When  one  m.  of  quinium  sulphate,  872  parts,  is  treated  with  one 
m.  of  tannin,  322  parts,  the  average  product  is  uniformly  the  same, 
1085  parts,  regardless  whether  potassic  acetate  or  sulphate  is  also 
