REVIEW  OF  PHARMACOPCEA  HELVETICA. 
313 
fusing  a  mixture  of  64  bismuth  in  powder,  3  carbonate  of  soda, 
and  7  sulphur.  The  purified  metal  is  dissolved  in  nitric  acid, 
the  solution  diluted  with  water,  filtered  through  gun  cotton  and 
crystallized.  The  crystals  are  first  triturated  with  4  parts,  and 
then  mixed  with  25  parts  distilled  water. 
It  was,  we  believe,  Duflos  who  first  proposed  the  preparation 
of  ternitrate  because  it  crystallized  free  from  arsenic ;  his  pro- 
cess was  subsequently  adopted  into  most  pharmacopoeias  of  conti- 
nental Europe,  and  is  substantially  the  above.  The  test  for 
arsenic  can  scarcely  be  considered  delicate  enough  ;  it  consists 
in  precipitating  the  solution  in  nitric  acid  by  sulphuretted  hy- 
drogen, digesting  with  sulphuret  of  ammonium,  and  treating  the 
filtrate  with  hydrochloric  acid. 
Calcium  sulfuratum.  Equal  parts  of  burned  lime  and  sublimed 
sulphur  are  ignited  for  half  an  hour  in  a  Hessian  crucible. 
Chininum  sulfuricum  is  prepared  in  chemical  manufactories, 
but  is  tested  for  its  purity  by  the  usual  tests. 
Chininum  purum  is  quinia  precipitated  by  caustic  soda. 
Chloroformium  is  prepared  by  adding  to  a  mixture  of  15  parts 
chlorinated  lime  (containing  one-fifth  active  chlorine)  and  90 
parts  hot  water,  one  part  alcohol  of  '837,  as  soon  as  the  tempe- 
rature has  reached  70°  C.  (158°  F.)  The  crude  product  is 
washed  with  water,  then  treated  with  sulphuric  acid  (quantity 
not  given),  rectified  from  a  steam  bath,  and  preserved  from  con- 
tact with  the  light.  Spec.  grav.  1*49.  The  total  absence  of 
alcohol  is  proved  by  the  bichromate  of  potassa  test.  Litmus, 
sulphuric  acid  and  nitrate  of  silver  are  not  affected. 
According  to  our  experience  on  a  large  scale,  this  process  is 
objectionable  for  the  large  amount  of  water  employed,  and  the 
high  heat.  With  some  modifications,  the  process  of  B.  Hirsch 
(see  Am.  Journ.  Ph.  1862,  p.  42)  has  given  us  the  best  results. 
For  purifying  crude  chloroform,  the  directions  of  our  pharmaco- 
poeia leave  little  to  desire.  In  regard  to  the  specific  gravity, 
and  to  the  total  absence  of  alcohol,  we  have  expressed  our  views 
on  another  occasion,  and  reiterate  from  experience  since  had, 
that  the  addition  of  sufficient  pure  alcohol  to  reduce  the  gravity 
to  about  1*480,  is  preferable. 
Cuprum  sulfuricum  ammoniatum  is  precipitated  by  alcohol 
from  a  solution  of  sulphate  of  copper  in  ammonia. 
