614  Gleanings  from  the  German  Journals.  {Am"iec.r,'Sarm* 
is  preferable  to  allow  only  the  vapors  of  these  mixture  to  come  in 
contact  with  the  caoutchouc,  as  the  latter  in  dissolving  will  leave  the 
impurities. — W.  Lascelles  [Bayr.  Gezv.  u.  Ind.  BL),  Pharm.  Central- 
halle,  T890,  654. 
Methylal,  on  account  of  its  low  boiling  point,  42 0  C,  and  its  easy 
volatilization,  is  coming  into  use  in  the  extraction  of  volatile  prin- 
ciples, especially  in  the  extraction  of  perfumes.  Experiments  made 
with  violets  prove  its  success  in  extracting  delicate  odors. —  Chemiker 
Ztg.,  1890,  1474.  "     .  • 
Detection  of  biliary  pigments  in  urine. — To  4  or  5  cc.  of  slightly 
warmed  urine  5  to  10  drops  tincture  of  iodine  are  added,  agitating 
after  the  addition  of  each  drop ;  in  the  presence  of  biliary  pigments 
a  pretty  olive-green  coloration  is  produced.  Excess  of  tincture  of 
iodine  will  produce  a  dirty  brown-red  color;  normal  urine  at  first 
decolorizes  the  iodine  solution,  then  gives  a  red  coloration,  and  on 
addition  of  an  excess  of  iodine  a  dirty  brown-red  color. — S.  Kathrein, 
Pharm.  Post,  1890,  845. 
New  Synthesis  of  Indigo. — In  the  Chemiker  Zeitung,o{  October  I, 
L.  Lederer  publishes  *a  simple  method  by  which  this  valuable 
dye  can  be  obtained  :  2  grams  anilido-acetic  acid  are  slowly  added, 
with  stirring,  to  8-IO  grams  fused  sodium  hydrate  ;  the  fusion,  at 
first,  of  a  pale  yellow  color,  is  continued  until  a  pure  orange  color 
is  obtained.  The  cooled  mass,  by  dissolving  in  a  large  quantity  of 
water,  separates  the  indigo.  In  the  same  journal,  of  October  8, 
K.  Heumann,  apparently  independent  of  Lederer,  discovered  the 
same  synthesis.  What  Lederer  calls  anilido-acetic  acid  is  called  by 
Heumann  phenylglycocoll  (C6H.NHCH2COOH) ;  one  part  of  this 
compound  is  heated  with  two  parts  sodium  or  potassium  hydrate ;  at 
2600  C.  the  fusion,  with  effervescence,  assumes  a  dark  orange  color. 
The  fusion  dissolved  in  water,  without  access  of  air,  produces  a 
yellow  solution;  exposure  to  air,  passing  a  current  of  air  through 
the  solution,  or  addition  of  ferric  chloride  and  hydrochloric  acid,  will 
cause  the  precipitation  of  indigo.  Heumann  has  applied  for  patents 
and  transferred  all  rights  to  the  "  Badische  Anilin-  und  Sodafabrik." 
Examination  of  tragacanth — According  to  the  German  pharma- 
copoeia, tragacanth  mucilage  (1  :  50)  should  assume  a  yellow  color 
with  solution  of  soda.  L.  Reuter  finds  that  this  coloration  is  not 
produced  in  the  cold,  but  rapidly  if  the  mixture  be  heated  for  a  few 
