THE  TREE  PRODUCING  QUILLAIA  BARK. 
31 
A  NEW  METHOD  OF  PREPARING  SOLUTION  OF  CITRATE  OF 
MAGNESIA. 
By  Frederick  Stearns. 
Ia  this  method  a  freshly  prepared  solution  of  bi-carbonate 
magnesia,  of  known  strength,  is  employed,  which  is  converted 
into  the  citrate  by  the  addition  of  the  requisite  amount  of  citric 
acid,  and  at  the  moment  of  corking,  that  the  large  amount  of 
carbonic  acid  gas  then  liberated  may  be  preserved.  It  is  as  fol- 
lows : — Precipitate  magnesia  from  a  hot  solution  of  sulphate  of 
magnesia  by  adding  to  it  a  hot  solution  of  carbonate  of  soda  ;  it 
requires  10j  pounds  (troy)  of  sulphate  of  magnesia  to  12  pounds 
(troy)  of  carb.  soda. 
Wash  the  precipitated  magnesia  well  upon  a  linen  filter, 
drain,  and  having  ascertained  the  amount  of  water  contained  in 
a  sample  of  known  weight,  by  drying  and  calcining,  introduce 
the  moist  hydrate  into  a  suitable  apparatus ;  and  to  every  1,280 
grains  of  anhydrous  magnesia  the  moist  hydrate  contains,  add  one 
gallon  of  clean  soft  water,  (allowing,  of  course,  for  the  water 
already  mechanically  combined  with  the  hydrate,)  then  subject 
the  whole  to  the  action  of  carbonic  acid  gas  under  a  pressure  of 
ten  atmospheres  for  twenty-four  hours,  or  until  the  magnesia  is 
dissolved.  Having  drawn  it  off,  filter  and  prepare  the  solution 
of  the  citrate  as  follows  : — Introduce  into  twelve  ounce  strong 
bottles  ten  and  one  half  fluid  ounces  of  the  solution  and  one  and 
a  half  ounces  of  lemon  syrup,  not  acidulated  ;  and  having  the 
corks  ready  and  softened,  introduce  into  each  three  hundred  and 
sixty-six  grains  of  citric  acid  in  crystals  ;  cork  and  wire  immedi- 
ately. 
The  large  excess  of  carbonic  acid  which  this  solution  contains, 
renders  its  use  more  agreeable  than  when  prepared  after  the 
officinal  or  usual  methods.  I  have  not  found  it  to  deposit  the 
insoluble  citrate. 
From  the  Proceedings  of  the  American  Pharmaceutical  Association — 1857. 
NOTE  ON  THE  TREE  PRODUCING  QUILLAIA  BARK. 
By  Charles  Raymond. 
The  following  account  of  "  soap  bark"  originally  published  in 
the  "  Bullein  de  la  Societe  Imperiale  Zoologique  d 'acclimation ," 
