Am.  Jour.  Pharm.  1 
Nov.,  1883.  i 
Syrup  of  Wild  Cherry. 
559 
formula,  which  is  in  reality  only  adaptable  to  factories,  and  doubly 
strange  that  it  did  not  incorporate  such  an  excellent  and  simple  pro- 
cess as  that  ^iven  in  Fownes'  chemistry.  This  process  is  equally 
applicable  to  large  and  small  operations,  and  yields  a  definite  and  per- 
manent product,  and  is  therefore  unlike  that  of  either  of  the  official 
methods.  It  consists  in  decomposing  pure  potassic  cyanide  with  tar- 
taric acid  in  the  presence  of  water  and  alcohol,  as  follows : 
KCy  +  HJ=  Hey  +  KHT. 
Pure  potassic  cyanide  is  as  easily  obtainable  as  argentic  cyanide,  and 
is  ultimately  cheaper.  There  are,  strangely  enough,  but  few  among 
the  numerous  cyanides  tliat  are  available  for  the  purpose  of  generating 
cyanhydric  acid  fit  for  medicinal  use.  Soluble  or  insoluble  they  are 
mostly  indefinite  and  intractable  substances.  Mercuric  cyanide,  which 
might  be  so  useful  for  this  purpose,  is  much  to  be  regretted  undecom- 
posable  by  those  acids,  which  would  render  the  complete  removal  of 
the  mercury  possible.  Hydric  sulphide  completely  decomposes  it,  and 
hence  the  writer  attempted  to  employ  the  oxysulphides  of  antimony 
for  this  purpose.  Although  these  methods  generated  cyanhydric  acid 
abundantly  and  promptly,  they  yet  failed  to  precipitate  the  mercury 
completely.  Owing  to  the  great  affinity  of  mercury  for  the  compounds 
of  carbonic  sulphide  (also  called  carbon  disulphide),  it  may  be  that 
some  such  combination  could  be  found  to  answer  the  purpose. 
The  formula  for  cyanhydric  acid  transcribed  from  Fownes'  is  as 
follows : 
Potassic  cyanide,  pure,  .         .         65  parts. 
Tartaric  acid,     .         .         .         .        150  " 
Alcohiol,   675  " 
Water  sufficient  to  mal?:e        .         .  1538 
Mix  the  potassic  cyanide  and  tartaric  acid  with  500  parts  of  water, 
in  a  well-stopped  bottle,  or  dissolve  each  separately  in  250  parts  of 
water,  and  mix  the  solutions ;  then  add  the  alcohol  and  sufficient  more 
water  to  make  1538  parts.  The  alcohol  may  also  be  mixed  with  500 
parts  of  water,  first  the  two  salts  be  then  added,  and  enough  water  to 
make  1538  parts  as  before.  After  the  hydropotassic  tartrate  has  sub- 
sided as  a  heavy  crystalline  powder,  the  clear  supernatant  liquid  is 
decanted. 
The  yield  of  official  acid  is  1350  parts,  but  the  generated  cream  of 
tartar  weighs  188  parts,  thus  making  the  1538  parts  as  above  directed. 
The  solution  contains  mere  traces  of  the  acid  tartrate. 
