346 
Magnesium  Citrate. 
Am.  Jour.  Pharm. 
July,  1902. 
The  solution  of  magnesium  citrate  is  a  favorable  medium  for  the 
development  of  these  micro-organisms,  and  while  its  preparation  has 
caused  a  very  wide  diversity  of  opinion  among  pharmaceutical 
writers,  still  some  appear  to  have  pursued  rational  methods  of  prepa- 
ration. Some  suggest  the  boiling  of  the  water  before  adding  to  the 
syrup  and  magnesia  solution,  stating  that  it  will  thus  keep  indefi- 
nitely. Fifteen  minutes'  boiling  for  three  successive  days  would  be 
required  for  this  method,  the  entire  solution  being  used.  Others 
suggest  placing  the  filled  bottles  into  a  pan  of  boiling  water  for  half 
an  hour.  This  method  would  be  effective  if  the  bottles  were  placed 
in  an  Arnold  sterilizer  for  three  consecutive  days,  fifteen  minutes 
each.  Samples  sterilized  by  this  method  in  our  laboratory,  with  an 
Arnold  form,  kept  ior  three  months  without  the  formation  of  the 
slightest  sediment.  Another  method,  without  the  aid  of  steriliza- 
tion, is  to  place  the  syrup  in  the  bottles,  then  the  solution  of  mag- 
nesium carbonate,  water  next,  the  crystals  of  potassium  bicarbonate 
being  the  last  addition.  Stopper  and  set  aside  without  the  slightest 
agitation.  The  sediment  in  this  solution  appeared  a  few  days  later 
than  in  the  pharmacopceial  solution. 
Experiments  showed  that  the  micro-organisms  appear  in  three  to 
five  days  in  the  official  preparation.  Samples  made  from  tap  and 
distilled  water,  with  varying  amounts  of  syrup  of  citric  acid,  required 
the  same  number  of  days'  incubation  at  room  temperature. 
As  a  result  of  his  experiments  the  writer  proposes  a  method  as  fol- 
lows :  "  Place  the  filtered  magnesium  citrate  solution  in  bottles  with 
the  syrup  of  citric  acid  and  distilled  water,  then  small  plugs  of  cotton 
between  the  rubber  stopper  and  neck  of  the  bottle  and  sterilize  for 
three  days,  fifteen  minutes  each  day.  The  autoclav,  or  the  pres- 
sure sterilizer,  requires  but  twenty-five  minutes  no°  C.  under  6 
pounds  pressure. 
Take  small  vials,  2  drachms  each,  add  35  grains  potassium  bicar- 
bonate, plug  with  cotton,  and  place  in  a  dry  oven  or  sterilizer  for 
one  hour  at  1500  C.  or  3020  F.  When  the  bottles  containing  the 
solution  and  salt  are  cool  enough,  carefully  remove  cotton  from  each, 
adding  the  contents  of  the  vial  to  the  syrupy  solution,  stopper 
tightly  and  dispense  as  needed.  The  solution  thus  prepared  is  a 
stable  and  pleasant  cathartic,  a  sweet,  aromatic,  effervescing  and 
carbonated  beverage,  and  yields  a  profit  of  65  per  cent. 
The  organisms  predominating  in  the  different  specimens  ex- 
