214 
Current  Literature. 
(Am.  Jour.  Pharm. 
I-     Marctu  1918. 
to  the  formation  of  a  violet  coloration,  due  to  the  production  of  a 
ferric  compound  of  dioxytartaric  acid.  Investigation  'by  Deniges 
revealed  that  while  this  reaction  was  unsatisfactory  for  the  detection 
of  tartaric  acid,  it  was,  under  certain  conditions,  satisfactory  for 
revealing  quite  minute  traces  of  hydrogen  peroxide.  Experimenta- 
tion showed  that  the  following  test  could  be  relied  on :  Two  mils  of 
a  5  per  cent,  solution  of  tartaric  acid  and  one  or  two  drops  of  ferrous 
ammonium  sulphate  of  the  same  strength  are  placed  in  a  test-tube, 
and,  after  shaking,  one  or  two  drops  of  hydrogen  peroxide  are 
added ;  when  the  hydrogen  peroxide  is  very  much  diluted,  as  much 
as  two  mils  of  it  may  be  added.  After  agitation  and  making  alkaline 
with  sodium  hydroxide,  a  violet  coloration  is  formed  in  the  presence 
of  as  little  as  0.04  to  0.05  of  a  milligram  of  oyxgen.  (Ann.  Chim. 
Anal.,  1917,  22,  193,  through  The  Analyst,  Dec,  1917,  page  403.) 
J.  K.  T. 
Test  for  Nitrates. — This  test  is  carried  out  by  adding  to  the 
suspected  nitrate  a  crystal  of  resorcinol  and  a  little  brucine,  cover- 
ing the  whole  with  a  few  drops  of  concentrated  sulphuric  acid.  In 
a  few  minutes  a  deep  blue  coloration  develops  around  the  crystal 
of  resorcinol  and  gradually  diffuses  throughout  the  whole  of  the  acid. 
On  dilution  with  water  the  color  disappears,  but  a  greenish-blue 
precipitate  is  formed. 
The  above  test  is  also  a  ready  means  of  distinguishing  a  nitrate 
in  the  presence  of  bromides  and  iodides.  Nitrites  also  respond  to 
this  test. 
J.  K.  T. 
colorimetric  methods  for  the  estimation  of  very  small  quantities 
of  Morphine. 
I.  Georges  and  Gascard's  Iodic  Acid  Method. — The  authors 
employ  a  modification  of  this  method.  Instead  of  using  a  Duboscq 
colorimeter,  they  prepare  a  scale  of  colors  by  diluting  a  faintly  acid 
solution  of  morphine  in  about  N/10-hydrocbloric  acid  to  a  concen- 
tration of  1  in  1,000  and  then  prepare  from  this  a  series  of  solutions 
of  concentrations  down  to  1  in  10,000.  Equal  volumes  (10  Cc.)  of 
these  solutions  are  treated  with  5  Cc.  of  5  per  cent,  iodic  acid  solu- 
tion, and  the  yellow  colorations  are  examined  after  about  half  a 
minute.  The  differences  in  color  are  more  pronounced  in  the  more 
dilute  solutions.    Whilst  morphine  can  be  thus  detected  at  a  con- 
