5S 
Japanese  Lac. 
{  Am.  Jour.  Phariri. 
I    February,  190(i. 
by  pouring  into  strong  alcohol.  The  precipitate  was  dissolved  in  a 
small  quantity  of  water  and  reprecipitated  with  alcohol.  By  repeat- 
ing the  operation  several  times  and  finally  washing  with  ether  and 
drying  in  an  exsiccator,  it  was  obtained  perfectly  white  and  easily 
reduced  to  powder.  In  physical  appearance  it  is  similar  to  powdered 
acacia.  When  so  prepared  the  gum-enzyme  is  very  active,  rapidly 
changing  fresh  tincture  of  guaiac  to  a  deep  blue.  If  an  emulsion  is 
made  of  the  gum  enzyme  and  the  separated  resins,  it  soon  changes 
to  black,  but  if  a  solution  of  the  gum-enzyme  is  heated  before  mix- 
ing with  the  resins,  no  change  takes  place. 
Tests  for  Nitrogen} — The  gum-enzyme  was  tested  for  nitrogen  by 
the  Lassaigne  test,  which  consists  in  heating  the  substance  with 
metallic  potassium  and  converting  the  cyanide  so  formed  into  Prus- 
sian blue.  This  test  and  various  modifications  of  it  failed  to  detect 
the  presence  of  nitrogen. 
When  the  gum-enzyme  is  heated  in  a  tube  with  soda-lime  or 
potassium  hydroxide  the  vapors  rapidly  change  red  litmus  to  blue, 
but  no  odor  of  ammonia  could  be  detected.  Professor  Tschirch 
thought  the  odor  similar  to  pyrrol.  By  using  larger  quantities  and 
condensing  the  vapors,  the  distillate  gave  all  of  the  tests  for  pyrrol. 
Another  evidence  of  the  presence  of  nitrogen  was  obtained  as 
follows  :  An  ordinary  open  combustion  tube  was  filled  with  copper 
oxide  and  ignited  in  a  current  of  oxygen.  After  partially  cooling 
a  platinum  boat  containing  the  gum-enzyme  was  introduced,  and 
burned  in  a  current  of  oxygen.  The  products  of  combustion  were 
conducted  into  a  potash  bulb  containing  a  solution  of  potassium 
hydroxide,  prepared  from  metallic  potassium,  and  water  distilled 
with  potassium  permanganate.  Just  before  the  combustion  the  solu- 
tion was  tested  and  found  to  be  free  from  nitrogen  compounds. 
After  the  combustion  the  solution  gave  with  diphenylamine  the  blue 
color  characteristic  of  nitrates ;  with  brucine  and  sulphuric  acid  a 
red  color  and  with  sulphuric  acid  and  sulphate  of  iron  the  brown 
ring  test. 
Separation  of  Gum  from  the  Enzyme. — H.  Yoshida  states  that  after 
removal  of  the  resins  by  alcohol  and  extracting  the  residue  with 
cold  water,  and  then  boiling  the  solution,  he  obtained  a  white 
1  For  a  detailed  report  of  nitrogen  in  gums,  see  Am.  Jour.  Pharm.,  77, 
p.  255,  1905,  also  Pharm.  Centralhalle ;  1905,  p.  501. 
1 
