2  5^  Gleanings  from  the  German  Journals.  {^'^•^^^•Jto" 
passes  a  stream  of  hydrogen  sulphide  through  the  latter  solution.  The 
iodine  is  converted  into  hydrogen-iodide,  and  this  is  absorbed  by  the 
supernatant  water,  forming  aqueous  hydriodic  acid,  while  the  separated 
sulphur  is  dissolved  by  the  carbon-bisulphide,  forming  a  heavy  oily  solu- 
tion. As  soon  as  the  violet  solution  of  the  iodine  acquires  a  wine-yellow 
color  the  transformation  is  complete,  the  two  distinct  layers  are  sepa- 
rated, and  the  aqueous  hydriodic  acid  is  boiled  for  a  few  minutes  iti 
order  to  expel  hydrogen  sulphide  if  present;  it  is  then  chemically  pure, 
atid  can  be  used  for  preparing  the  various  iodides. — Schw.  Wochenschr. 
f.  Pharm.^  Feb.  13,  1880,  p.  54,  from  Jahresber.  d.  Phys.  Ver.  z. 
Frankf. 
Borocitric  Acid  and  its  Salts. — Ed.  Scheibe  proved  that  citric 
acid  forms  with  boracic  acid  a  soluble  compound,  the  two  constituents 
always  uniting  in  the  proportion  of  2  molecules  of  citric  and  i  mole- 
cule of  boracic  acid.  The  corresponding  proportions  by  weight  are: 
I  part  by  weight  of  boracic  acid,  and  7  parts  of  citric  acid.  Boro- 
citric acid  can  be  prepared  either  by  adding  the  boracic  acid,  with  con- 
stant stirring,  to  a  solution  of  the  citric  acid  in  boiling  water,  or  by 
adding  the  citric  acid  to  the  boracic  acid  suspended  in  boiling  water, 
and  continuing  to  heat  until  a  complete  solution  is  obtained,  or  by  mix- 
ing both  acids  with  water,  and  heating.  On  evaporating  an  aqueous 
solution  of  borocitric  acid  to  dryness,  a  solid,  amorphous,  light  gray 
mass  is  obtained,  which  is  readily  soluble  in  water  and  in  strong  alco- 
hol. When  subjected  to  dialysis  it  dialyzed  unaltered.  While  evap- 
orating, some  of  the  boracic  acid  volatilized  with  the  water.  By  allow- 
ing a  very  concentrated  solution  of  borocitric  acid  to  evaporate  very 
slowly,  the  acid  was  obtained  as  a  decidedly  crystalline  ribrous  mass. 
The  crystalline  borocitric  acid  differs  from  the  amorphous  only  in  being 
less  compact  and  having  a  snow-white  color;  in  all  other  respects  it 
closely  resembles  the  amorphous  acid  into  which  it  is  soon  transformed, 
even  when  kept  in  closed  vessels.  Both  compounds  are  not  altered 
by  the  air,  unless  the  atmosphere  is  very  moist,  when  they  deliquesce. 
The  borocitrates  of  the  alkalies  are  permanent  salts,  soluble  in  water, 
while  the  salts  of  the  heavy  metals  are  partially  soluble  in  water  and 
partially  insoluble,  the  boracic  acid  apparently  not  being  combined  very 
firmly.  All  salts  of  borocitric  acid  color  turmeric  paper  brownish-red, 
and  are  decomposed  by  stronger  acids,  which  separate  the  boracic  acid. 
Potassium  bihorocitrate  is  the  only  salt  which  has  been  obtained  in  crys- 
tals so  far. — Phar.  Zeits.  f.  Russland ;  Schw.  Wochenschr.^  Feb.  13, 
1880,  p.  50-53. 
