AmjSe,r,8P,8arm'}  Gleanings  from  the  German  Journals. 
295 
digested  acetic  acid,  to  which  one  or  two  per  cent,  of  nitric  acid  had 
been  added,  for  half  an  hour  on  a  warm  sand-bath,  without  allowing 
the  acid  to  boil,  and,  after  the  addition  of  chloro-hydric  acid,  failed  to 
perceive  any  precipitation  of  the  silver  salt.  I  generally  test  it  by 
first  neutralizing  the  acid  with  carbonate  of  soda,  and,  after  the  addi- 
tion of  an  equal  volume  of  sulphuric  acid,  pure,  free  from  nitric  acid 
or  selenium,  allow  the  mixture  to  cool,  and  add  a  concentrated  aqueous 
solution  of.  sulphate  of  the  protoxide  of  iron,  without  allowing  its 
admixture.  If  the  least  trace  of  nitric  acid  is  present  a  dark  ring  will 
be  formed  where  the  fluids  are  in  contact. 
The  remaining  impurities  most  common  in  acetic  acids,  and  the 
means  of  detecting  them,  are  alluded  to  in  the  table  following  : 
ADULTERA- 
TIONS. 
1  Water  
2  Empyreumatic  oils 
3  Nitric  acid  
4  Muriatic  acid  , 
5  Sulphuric  acid  , 
6  Sulphurous  
7  Lead  , 
8  Copper  , 
9  Lime..  
10  Formic  acid  
TESTS. 
1  Hydrometer  
2  Odor  
2  Boiled  with  an  equal  volume  of  sul- 
phuric acid. 
3  Neutralized  with  carb.  of  potassa, 
with  the  addition  of  pure  sulph. 
acid,  and  then  concentrated  solu- 
tion sulphate  iron. 
4  Addition  of  nitrate  of  silver  
5  Chloride  of  barium  
6  Sulphuretted  hydrogen  
7  Sulphide  of  ammonium  
8  Sulphide  of  ammonium.  
9  Oxalate  of  ammonia..  
10  Boiled  with  an  equal  volume  of  sol- 
ution nitrate  silver  or  proto-nitrate 
mercury. 
PURE. 
1  Sp.  gr.  1-047...... 
2  Agreeable  smell 
2  The  acid  is  not 
colored. 
3  No  dark  ring  at 
point  of  con- 
tact of  the  iron 
solution. 
4  No  precipitate.. 
5  No  precipitate.. 
6  No  precipitate.. 
7  No  precipitate.. 
8  No  precipitate.. 
9  No  precipitate.. 
10  No  precipitate. 
IMPURE. 
1  Lighter. 
2  Empyreumatic  odor. 
2  The  acid  is  colored. 
3  A  dark  ring. 
4  Precipitate. 
5  Precipitate. 
6  Milkiness.  , 
7  Black  precipitate. 
8  Black  precipitate. 
9  White  precipitate. 
10  Separates  the  nitrates 
by  reducing  them  to 
the  metallic  state. 
GLEANINGS  FROM  THE  GERMAN  JOURNALS. 
By  L.  von  Cotzhausen,  Ph.G. 
Elastic  Gelatin  Capsules. — DetenhofF  recommended  to  prepare 
them  from  1  part  of  gelatin,  2  of  water  and  2  of  glycerin,  which,  how- 
ever, does  not  give  a  satisfactory  mass,  the  capsules  becoming  opaque 
as  the  water  gradually  evaporates.  The  following  formula  is  prefer- 
able, capsules  made  by  it  remaining  transparent  and  elastic  for  years. 
Take  1  part  of  gelatin,  2  parts  of  water  and  4  parts  of  glycerin  ;  soak 
the  gelatin  in  the  water,  and  dissolve  with  a  gentle  heat ;  add  the 
glycerin,  and  evaporate  on  a  water-bath  until  5  parts  remain,  that  is 
until  all  the  water  is  evaporated  ;  into  this  warm  melted  mass  dip  the 
moulds,  and  proceed  as  usual. — Pharm.  Ztg.  f.  Russl.^  March  15,  p.  164. 
