242 
Practical  Notes. 
f  Am.  Jour.  Pharm. 
\      May,  18S2. 
PKACTICAL  NOTES  FKOM  VARIOUS  SOURCES. 
By  the  Editor. 
Purification  of  Naphthalin — Crude  naphthalin  is  fused,  well  mixed 
with  sulphuric  acid  (such  of  60°  is  sufficiently  strong),  and  afterwards 
with  5  per  cent,  of  finely-powdered  black  oxide  of  marganese  gradu- 
ally added.  After  15  or  20  minutes  the  mixture  is  cooled,  the  naph- 
thalin is  repeatedly  melted  with  water  and  with  weak  soda  solution, 
and  finally  distilled.  Other  oxydizing  agents  may  be  used  in  place  of 
manganese.  Thus  purified,  naphthalin  remains  perfectly  white. — Pep. 
Anal.  Chem.,  1881,  No.  21 ;  Phar.  Centralh.,  1882,  No.  3. 
The  Origin  of  Benzoic  Acid  is  best  determined,  according  to 
O.  Schlickum,  by  the  peculiar  empyreumatic  odor.  Pure  benzoic  acid 
does  not  reduce  potassium  permanganate  ;  if  a  reduction  takes  place  it 
is  usually  due  to  cinnamic  acid.  The  reaction  is  best  performed  with 
the  free  acid  or  in  the  form  of  sodium  salt,  but  not  with  a  boiling 
alkaline  liquid  which  is  apt  to  cause  a  reduction  from  various  causes. 
If  0*10  gram  of  benzoic  acid  or  its  sodium  salt  is  agitated  with  5 
grauLS  of  water  and  after  the  addition  of  10  or  15  drops  of  one-tenth 
per  cent,  solution  of  potassium  permanganate  the  color  of  the  latter  is 
discharged,  the  benzoic  acid  has  most  likely  been  prepared  from  Siam 
benzoin.  If  a  red  tinge  is  permanently  produced  by  3  or  4  drops  of 
chameleon  solution,  the  acid  was  probably  artificially  prepared  from 
toluol ;  if  such  an  acid  be  resublimed  in  the  presence  of  a  small  quan- 
tity of  benzoin,  the  product  behaves  nearly  the  same  as  the  acid 
obtained  from  Siam  benzoin.  The  mixed  silver  salts  of  cinnamic  and 
benzoic  acid  may  be  separated  by  boiling  water,  in  which  the  silver 
cinnamate  is  insoluble. — Phar.  Zeitung,  1882,  p.  24.  See  also  A7n. 
Jour.  Phar.,  1882,  p.  56. 
Preservation  of  Ergot. — Emil  Ferret  directs  the  ergot  to  be  bruised, 
and  dried  at  40°C.,  then  powdered  and  dried  at  80°C.,  then 
in  a  percolator  exhausted  with  strong  ether,  after  which  the 
powder  is  dried  at  35°C.  for  several  hours,  the  heat  being  after- 
wards raised  to  40,  to  60,  to  80  and  for  a  few  moments  to 
100°C.  (See  also  ''Amer.  Journ.  Pharm.'^  1881,  p.  457.)  The  pow- 
der kept  in  vials,  retains  a  little  ether,  which  after  six  months,  is  given 
off  on  heating  to  110  or  116°C.— Pull.  gen.  de  Ther.,  March,  1882,  p. 
202  to  204.  ■ 
Stanislas  Martin  [Ibid.,  p.  245)  directs  attention  to  the  fact  that  as 
