Am'juiyfimarm'}      Gleanings  from  the  German  Journals.  357 
hour  the  mixture  is  filtered,  the  filtrate  acidulated  with  dilute  H2S04, 
and  again  filtered  from  the  precipitate ;  this  filtrate  is  neutralized  with 
potassium  hydrate,  concentrated  to  about  300  cc,  acidulated  with  sul- 
phuric acid  and,  at  once,  agitated  with  ether ;  if  the  precipitate  is  sol- 
uble in  ether  only  azaleinic  acid  C9H1604  is  present,  formed  by  the 
oxidation  of  oleic  acid,  and  the  oleic  acid  was  free  from  linoleic  acid ; 
if  the  precipitate  is  insoluble  in  ether  it  is  removed  by  filtration, 
purified  by  recrystallization  from  alcohol  or  water  in  presence  of  animal 
charcoal  and  the  melting  point  of  the  dried  crystals  determined,  should 
this  be  above  160°  linoleic  acid  was  certainly  present.  As  a  control 
experiment  the  combining  value  of  the  crystals  can  be  determined, 
which  should  approach  150. — K.  Hazura,  Chem.  Report,  1889,  168. 
Chemical  examination  of  resins,  gum-resins  and  balsams. — The 
suggestion  made  by  Kremel  to  examine  the  above  classes  of  substances 
by  HiibPs  method  of  examining  waxes  (see  Am.  Jour.  Pharm.,  1888, 
561),  was  carried  out  by  Dieterich  with  results  which  indicate  the 
value  of  the  method  in  examining  the  balsams.  The  figures  given 
represent  the  extremes : 
Resins  and  Gum-resins.    Acidity-    Ester-     Saponification  figures. 
Ammoniac,  purified   132  73  205 
Colophony   157-169'6     
Benzoin,  Siam   140  35  175 
Sumatra   112  51*4  163-4 
Balsams. 
Canada   84  86'8     
Copaiba,  Para   52- 3  532     
"       Maracaibo   737-86-8    
East  India   6-5-7-4  10-3-11-2  16-8  18  6 
Mecca,  crude   427  43-8     
purified   40.1     
Peru   50-4-58-8  196-201-6  246-4-254"8 
Tolu,  crude   121  126  49  60  6  173-1-181-6 
"    purified   154  158  14-32-6  172-6-186'6 
Styrax,  crude   64*4-87  87-162'4  157-249-4 
Terebinth,  commun   108'2     
"        venet   78'4     
Attention  is  called  to  the  differences  in  acidity  of  the  varieties  of 
copaiba,  also  that  only  the  East  Indian  contains  esters  ;  so  it  is  possi- 
ble to  distinguish  the  varieties  and  even  approximate  admixtures. 
The  results  of  the  balsam  examinations  with  the  exception  of  styrax 
are  fairly  uniform  and  encouraging  to  further  work. — (Helf.  Ann.) 
Pharm.  Post,  1889,  336. 
