528  British  Pharmaceutical  Conference.    {Am  arm' 
ammonii  citras  as  a  constituent.  For  instance,  one  mixture  consisting  of  forty- 
grains  of  the  citrate  to  eight  ounces  of  water  gradually  became  turbid,  depos- 
iting a  brown  precipitate,  and  the  liquid  eventually  becoming  colorless  or 
nearly  so.  When  the  mixture  was  made  up  with  hard  instead  of  distilled  water, 
part  of  the  precipitate  was  buff-colored  and  part  black.  At  first  an  explana- 
tion of  the  instability  was  looked  for  in  Mr.  Umney's  opinion,  expressed  in 
The  Pharmaceutical  Journal  in  1873,  that  the  official  compound  was  deficient  in 
ammonium  citrate,  and  indeed  a  slightly  better  result  was  obtained  upon  the 
addition  of  a  little  of  that  salt.  But  that  this  was  not  a  full  explanation,  was 
shown  by  the  fact  that  a  sample  that  yielded  32  per  cent,  of  ferric  oxide  on 
incineration  was  more  stable  than  one  that  contained  only  307  per  cent.  It 
was  then  observed  that  the  residue  from  an  incineration  gave  off  the  odor  of 
sulphuretted  hydrogen  upon  the  addition  of  hydrochloric  acid,  and  the  pres- 
ence of  sulphate  in  the  original  citrate  was  confirmed  by  the  barium  test.  A 
suggestion  that  a  manufacturer's  modification  of  the  official  process  for  citrate 
of  iron  and  ammonium,  in  precipitating  the  ferric  hydrate  with  caustic  soda 
and  the  use  of  hard  water,  might  have  introduced  a  trace  of  sulphate,  was 
negatived  by  the  fact  that  a  sample  in  the  preparation  of  which  the  ferric  hy- 
drate was  known  to  have  been  precipitated  by  ammonia,  gave  palpable  quan- 
tities of  sulphate  and  only  traces  of  lime.  Mr.  Proctor  himself  refers  the 
contamination,  which. in  some  cases  equalled  2  per  cent,  of  sulphuric  anhy- 
dride, to  the  conditions  under  which  the  citrate  is  manufactured  on  the  large 
scale.  It  is  known  that  when  ferric  hydrate  is  precipitated  from  the  sulphate 
it  will  contain  a  notable  quantity  of  basic  sulphate,  unless  the  caustic  alkali 
used  in  the  precipitation  is  kept  continually  in  free  excess.  But  when  a  large 
stream  of  iron  liquor  is  poured  into  alkali  this  condition  is  not  present,  since 
the  liquid  immediately  surrounding  the  point  of  impact  will  always  contain 
iron  in  excess  of  alkali  for  a  sufficiently  long  time  to  allow  of  the  formation  of 
basic  sulphate,  which  may  escape  decomposition  even  after  the  mixture  be- 
comes more  complete.  The  remedy  suggested  is  to  allow  the  two  solutions  to 
mingle  in  thin  streams  so  regulated  that  the  correct  equivalent  proportions  are 
pretty  closely  maintained.  Mr.  Proctor's  paper  also  contained  some  interesting 
observations  on  the  retardation  of  the  precipitation  of  barium  sulphate  in  the 
presence  of  a  citrate. 
Easton's  Syrup. — Mr.  Clague  called  attention  to  the  fact  that  samples  of 
Easton's  syrup  are  sometimes  met  with  which  through  the  influence  of  a  low 
temperature  have  undergone  such  change  as  to  render  them  unfit  for  use.  In 
one  case  the  "  syrup  "  was  a  jelly-like  mass,  with  long  needle-shaped  crystals 
and  tufts  of  crystals,  and  a  smaller  amount  of  fine  white  precipitate  showing. 
"Warmth  brought  about  solution,  but  precipitation  again  took  place  on  cooling 
to  about  32°  F.  It  was  found,  however,  that  the  addition  of  25  per  cent,  of 
water  sufficed  to  maintain  solution  at  the  lower  temperature,  and  that  this  was 
not  affected  upon  the  addition  of  the  quinine,  strychnine  and  ferrous  phosphate 
requisite  to  bring  it  up  to  Easton's  strength.  The  high  specific  gravity  of  the 
samples  pointed  to  excess  of  sugar  as  the  source  of  trouble,  and  it  was  ascer- 
tained that  the  precipitation  and  gelatinous  appearance  stood  in  direct  relation 
to  the  quantity  of  sugar  present.  Mr.  Clague  therefore  recommended  that 
where  Easton's  syrup  finds  a  ready  use,  the  original  formula,  containing  35  per 
cent,  of  sugar,  should  be  adhered  to  ;  but  that  where  it  is  not  in  so  frequent 
