SYRUP  PHOSPHATES  OF  IRON,  QUINIA  AND  STRYCHNIA.  323 
of  the  phosphates,  presented  no  very  serious  obstacles,  but  the 
attempt  at  combining  this  with  the  sugar  utterly  failed.  The 
solution  of  the  phosphates,  already  containing  some  sugar,  was 
filtered  directly  upon  the  remaining  sugar  contained  in  a  bottle, 
and  the  mixture  shaken  occasionally  until  the  sugar  was  dis- 
solved. During  this  operation  a  dense  and  very  permanent  foam 
was  formed,  equal  in  bulk  to  the  solution,  and  otherwise  remark- 
able for  the  readiness  and  abundance  in  which  it  could  be  pro- 
duced, even  by  slight  commotion,  and  which,  after  filtration  of 
the  syrupy  solution,  remained  without  much  diminution  of  bulk 
upon  the  filter  for  several  days,  and  was  then  thrown  away. 
The  liquid,  during  the  solution  of  the  sugar,  deposited  a  bulky 
gelatinous  sediment,  which  had  at  first  a  white  appearance,  but 
possessing,  when  more  compact,  a  bluish  tinge.  The  formation 
of  this  deposit  seemed  to  be  continuous,  as,  after  repeated  filtra- 
tion of  the  liquid,  the  gelatinous  precipitate  still  appeared,  and, 
although  accumulated  in  abundance  at  the  bottom,  the  liquid 
above  never  became  clear,  as  portions  of  the  precipitate  remained 
constantly  disseminated  throughout  the  whole. 
This  precipitation  may  have  its  limit  when,  after  the  greater 
portion  of  the  iron  has  become  insoluble,  a  highly  acid  salt  still 
remaining  in  solution  in  the  now  superabundant  excess  of  phos- 
phoric acid.  This  view  seems  plausible  from  the  fact  that,  after 
an  abundance  of  the  deposit  has  been  removed,  the  subsequent 
formation  of  it  is  more  moderate  and  somewhat  different  in  char- 
acter. For  instance,  on  the  liquid,  which  immediately  after  fil- 
tration is  perfectly  transparent  and  strongly  exhibits  the  pecu- 
liar tinge  characteristic  for  solutions  of  the  quinia  salts,  a  pelli- 
cle begins  to  form,  which,  when  sufficiently  heavy,  breaks  up, 
and  the  fragments  floating  about  in  the  liquid  are  gradually  de- 
posited. But  from  the  commencement  no  moderate  excess  of 
citric  or  phosphoric  acid  will  prevent  or  redissolve  the  pre- 
cipitate. 
A  portion  of  the  syrupy  solution  before  filtration,  with  the  ad- 
dition of  more  sugar,  was  heated,  contrary  to  directions,  with  a 
view  to  avoid  the  production  of  foam,  and  to  dissolve  the  deposit, 
but  this  only  had  the  effect  to  augment  the  voluminous  deposi- 
tion. 
