120  Bromotes  of  the  Cinchona  Alkaloids.    {AVS£.  ww?111' 
rheumatic  influence,"  the  large  proportion  of  easily  dissociated  oxy- 
gen present  being  supposed  to  add  to  its  physiological  activity.  These 
salts  were  all  prepared  by  double  decomposition  between  barium  bro- 
mate  and  the  corresponding  sulphates,  and  a  sample  of  each  is  pre- 
sented. On  platinum  or  porcelain,  heated  to  redness,  they  are  decom- 
posed with  explosive  violence,  leaving  a  very  slight  charred  residue. 
Barium  bromate  was  dissolved  in  boiling  water,  a  calculated  amount 
of  sulphate  of  quinine  added,  and  the  mixture  filtered.  The  filtrate 
was  of  a  violet  blue  color,  a  circumstance  I  am  unable  to  explain,  the 
suggestion  being  offered  that  it  may  be  due  to  a  compound  allied  to 
thalleioquin.  Almost  immediately,  the  solution  being  concentrated, 
crytals  began  to  separate  in  small  clusters.  These  were  redissolved  in 
a  large  quantity  of  water,  and  set  aside  for  a  few  days,  when  the  pro- 
duct was  procured  in  the  form  of  handsome  stellate  clusters  of  long, 
white  acicular  crystals.  These  were  dried  upon  filtering  paper.  Ex- 
posed to  the  air  for  nearly  a  month,  they  did  not  effloresce  nor  un- 
dergo any  noticeable  change.  The  solubility  in  water  is  very  slight, 
as  is  indicated  by  the  rapidity  with  wlych  crystals  form.  The  taste 
is  bitter,  and  the  reaction  slightly  acid.  Dropped  upon  a  heated  por- 
celain lid,  the  crystals  decompose  immediately  with  a  slight  explosion. 
Upon  concentrating  the  mother  liquor  the  blue  color  was  much  deep- 
ened, and  the  second  crop  of  crystals  had  a  violet  tinge,  which  can  be 
removed  by  solution  and  crystallization.  A  repetition  of  the  process 
in  somewhat  more  dilute  solution  gave  the  same  results,  except  that 
the  solution  was  but  very  slightly  colored  at  first,  but  the  crystals 
were  no  better,  and  upon  concentration  the  color  was  again  produced. 
Vinchonidine  bromate  was  next  prepared,  the  same  process  being 
used.  This  also  gave  a  blue  colored  solution,  but  the  salt  was  found 
to  be  much  more  soluble  than  the  preceding,  requiring  a  very  concen- 
trated solution  before  crystals  would  form.  The  first  that  were  pro- 
cured were  tested  for  quinine,  but  none  was  found.  The  easy  solu- 
bility of  the  salt,  together  with  the  color  complication,  made  the  pro- 
curing of  white  crystals  a  matter  of  considerable  difficulty.  By 
renewed  trials  with  fresh  materials,  and  recrystallizing  the  products 
repeatedly,  a  fairly  good  specimen  was  secured*  The  best  plan  would 
probably  be  to  evaporate  a  moderately  dilute  solution  spontaneously  in 
a  cool  place  or  in  vacuo.  In  heating  the  solution  to  concentrate  it, 
care  must  be  taken  to  see  that  the  process  be  not  carried  too  far,  as 
decomposition  is  likely  to  take  place  and  the  salt  to  be  spoiled,  even  if 
