AMTaJn0Tm4ABM-{    Purification  of  Grab  Orchard  Salt, 
PURIFICATION  OF  CRAB  ORCHARD  SALT. 
By  Richard  Y.  Mattison. 
Read  at  the  Pharmaceutical  Meeting,  December  16. 
Among  the  purgative  medicines  used  in  various  sections  of  this 
country,  none  are  more  rapidly  finding  favor  among  physicians  and 
the  general  public  than  the  salt  obtained  by  evaporating  the  waters 
of  the  springs  at  Crab  Orchard,  Lincoln  county,  Kentucky. 
As  the  salt  appears  in  our  market  it  is  of  various  degrees  of  color 
and  purity.  It  is  usually  prepared  by  concentrating  the  water  in 
iron  kettles  and  then  allowing  the  concentrated  water  to  stand  at  rest 
until  the  largest  portion  of  the  organic  matter  is  precipitated.  The 
supernatant  liquid  is  then  decanted,  more  or  less  care  being  used,  and 
evaporated.  The  yield  is  about  1  to  1.25  per  cent.,  ten  gallons  of 
the  water  yielding  about  a  pound  of  the  commercial  salt.  Much  more 
care  was  formerly  used  in  the  preparation  of  this  salt  than  now,  and 
of  late  years  the  salt  has  gradually  grown  more  and  more  impure, 
owing  to  the  ready  sale  found  for  it,  which  fact  was  noticed  in  a  letter 
from  the  proprietors  a  short  time  ago,  in  which  they  remarked  "  that 
the  supply  was  not  equal  to  the  demand." 
When  dissolved  in  water  the  solution  of  the  commercial  salt  pre- 
sents a  very  unsatisfactory  appearance,  and  is  certainly  very  far  from 
being  inviting  as  a  medicine.  This  should  be  remedied;  in  fact,  Crab 
Orchard  salt  should  never  be  dispensed  without  first  being  purified^ 
which  is  easily  done  by  the  following  process  (which  I  think  should 
be  performed  at  the  spring,  before  the  salt  is  ever  offered  to  the  mar- 
ket.) Dissolve  the  salt  in  boiling  water  and  filter  through  paper,  or, 
on  a  large  scale,  flannel  bags  are  best.  The  filtrate  is  then  evapo- 
rated carefully  to  dryness,  stirring  meanwhile  to  favor  granulation 
and  prevent  caking.  If  the  directions  are  carefully  followed,  the  pro- 
duct will  be  a  beautiful  snow-white  salt,  perfectly  soluble  in  water  ; 
one^which  the  pharmacist  can  recommend  and  dispense  with  satisfac- 
tion ;  more  active  than  the  ordinary  salt,  as  it  is  free  from  the  in- 
soluble earthy  admixtures  of  alumina,  calcium  sulphate,  etc.  The 
purified  salt  usually  contains  much  less  water  than  the  commercial, 
which  varies  very  much,  the  amount  ranging  from  35  to  50  per  cent., 
the  mean  being  usually  about  40  per  cent.  The  active  ingredients 
seem  to  be  principally  magnesium  and  sodium  sulphates,  also  a  con- 
siderable proportion  of  potassium  sulphate,  with  sodic  and  lithio 
