808 
SMALL- POX  REMEDY. 
The  filtered  liquid  is  evaporated  to  one-third  its  bulk,  and 
allowed  to  cool,  to  deposit  a  quantity  of  sulphate  of  potassa.  It 
is  then  mixed  with  its  own  volume  of  alcohol  of  about  90  per 
cent.,  which  causes  the  precipitation  of  almost  the  whole  of  the 
sulphate  of  potassa  (Anthon,  J.  Pr.  Oh.,  Vol.  14,  p.  25). 
•  The  solution  after  filtration  may  be  evaporated  to  dryness, 
and  yields  a  product  containing  only  a  trace  of  sulphate  of  po- 
tassa, and  of  sufficient  purity  without  further  crystallization,  for 
any  of  the  purposes  for  which  it  is  required, — whether  as  a  re- 
agent, {iron  test,)  the  precipitation  of  sulphocyanide  of  mercury 
for  "  Pharaoh's  Serpents,"  or  the  preparation  of  the  ammonium 
salt  for  photography.  Subsequent  crystallization  from  alcohol 
yields  the  salt  perfectly  pure. 
The  commercial  cyanide  of  potassium,  being  very  impure  from 
carbonate  and  cyan  ate  of  potassa,  is  not  so  well  adapted  for 
use  in  this  process  as  that  known  as  "granular  cyanide;"  the 
increased  price  of  the  latter  being  more  than  compensated  by 
the  larger  yield  and  improved  quality  of  the  product.  Good 
commercial  cyanide  gives,  however,  very  good  results. 
The  heat  required  is  not  great,  and  the  vessel  should  be  re- 
moved from  the  fire  as  soon  as  possible  after  the  formation  of 
the  sulphocyanide,  as  it  rapidly  decomposes  at  a  temperature  of 
fusion,  in  contact  with  the  air.  This  process  gives  equally 
satisfactory  results,  whether  small  or  large  quantities  are 
operated  upon,  and  has  been  perfectly  successful  in  the  hands  of 
the  writer  in  the  preparation  of  quantities  varying  from  two 
ounces  to  twenty-five  pounds.  The  amount  of  sulphocyanide 
obtained  is,  with  good  cyanide  of  potassium,  about  equal  to  the 
weight  of  the  latter  employed. 
Boston,  June  23,  1866. 
SMALL-POX  REMEDY, 
t Editor  Am.  Jour.  Pharm.    Dear  Sir  ; 
The  47th  number  of  Braithwaite's  Retrospect  for  July,  1868, 
gives  so  favorable  an  account  of  the  virtues  of  the  Sarracenia 
purpurea,  or  American  Pitcher-plant,  in  the  cure  of  the  small- 
pox and  measles,  that  I  was  induced  to  procure  a  quantity  of  it 
