Am.  Jour.  Pharm. 
June,  1905. 
} 
Nitrogen  in  Gums. 
255 
NITROGEN  IN  GUMS. 
By  A.  B.  Stevens, 
Pharmaceutical  Institute,  University  of  Bern,  Prof.  A.  Tschirch,  Director. 
I  became  interested  in  the  tests  for  nitrogen  while  conducting 
research  work  upon  Japanese  Lac,1  a  product  of  Rhus  vemicifcra, 
which  contains,  in  addition  to  other  constituents,  a  gum  and  an 
oxidizing  enzyme.  The  gum  and  enzyme  can  be  obtained  as  a 
white  powder  by  extracting  the  resin  with  alcohol,  dissolving  the 
residue  in  water  and  precipitating  with  alcohol.  By  re-dissolving 
and  re-precipitating  two  or  three  times,  it  can  be  obtained  perfectly 
white.  Finally  wash  with  ether  and  dry  in  an  exsiccator.  When 
so  prepared  the  enzyme  is  very  active,  rapidly  changing  tincture  of 
guaiac  to  a  deep  blue  color.  If  an  emulsion  is  made  with  the  gum- 
enzyme,  water  and  the  separated  resin,  it  soon  changes  from  yellow- 
ish-white to  black.  If  a  solution  of  the  gum  is  boiled  with  water, 
it  becomes  entirely  inactive.  It  is  a  generally  conceded  fact  that 
all  enzymes  contain  nitrogen. 
The  Lassaigne  test  for  the  detection  of  nitrogen  is  undoubtedly 
considered  the  most  reliable.  It  consists  in  heating  the  substance 
with  metallic  potassium  or  sodium  and  converting  the  cyanide  so 
formed  into  Prussian  blue.  This  test  was  applied  to  the  gum- 
enzyme,  but  failed  to  detect  the  presence  of  nitrogen.  According 
to  Kehrer  the  Lassaigne  test  must  be  modified  for  certain  pyrrol 
derivatives,2  and  cannot  be  applied  to  diazocompounds.3  In  view  of 
the  certainty  of  the  presence  of  nitrogen  and  the  general  reputation 
of  the  test,  it  was  repeatedly  tried  with  various  modifications.  The 
gum-enzyme  was  previously  mixed  with  dry  sodium  carbonate  and 
carefully  ignited.  The  rapidity  of  the  heating  was  varied.  In 
another  experiment  the  substance  was  placed  in  a  narrow  tube 
closed  at  one  end,  and  the  tube  drawn  out  to  contract  the  opening, 
small  pieces  of  sodium  were  then  introduced  and  the  tube  again 
contracted,  thus : 
\ 
GUM -ENZYME 
SODIUM 
/ 
\ 
1A  report  of  the  work  upon  Japanese  lac  will  follow  later. 
2Berichte,  35,  2,525  ;  1902. 
3Berichte,  17,  1,178  ;  1884. 
