Current  Literature. 
[Am.  Jour.  Pharm. 
January,  19 18. 
mixed  with  an  equal  weight  of  the  strong  acid.  The  crystals  which 
separate  at  o°  to  io°  C.  are  washed  with  ice-cold  nitric  acid.  The 
pure  nitrate  is  converted  into  oxide  by  heating  and  this  is  reduced 
by  fusion  with  potassium  cyanide.  Further  purification  is  effected 
by  melting  the  metal  under  paraffin,  and  removing,  by  means  of  a 
glass  spoon,  the  first,  and  purest,  crystals  formed.  Purified  bismuth 
melts  at  271  °  C,  and  when  pressed  into  wire  the  melting  point  is 
lowered  to  1950  C,  and  its  specified  electrical  resistance  is  then 
1.20.  Various  samples  of  bismuth  sold  as  pure  were  found  to  con- 
tain from  0.03  to  0.25  per  cent,  of  impurities.  The  method  for  test- 
ing for  impurities  is  detailed.  (F.  Mylius  and  E.  GroschufT,  Zeit. 
Anaeq.  Chew,.,  191 6,  96,  237,  through  /.  Chem.  Soc,  191 7,  112, 
(3),  37-) 
Biochemical  Reaction  to  Differentiate  Pyrocatechol, 
Hydroouinone  and  Resorcinol. — The  reaction  is  based  on  the 
property  of  the  enzyme  laccase  of  developing  a  blue  color  with  cer- 
tain phenols  in  presence  of  free  hydriodic  acid  and  starch.  The 
reaction  occurs  in  two  phases.  In  the  first  loss  of  phenolic  hydro- 
gen occurs  as  the  result  of  oxidation.  In  the  second,  much  more 
sensitive,  the  hydriodic  acid  is  reduced,  deprived  of  its  hydrogen, 
and  iodine  is  liberated.  The  reagents  necessary  are:  (1)  1 :  50  solu- 
tion of  soluble  starch,  containing  3:100  of  potassium  iodide;  (2) 
glycerin  maceration  of  Russula  delica  1:1,  or  other  fungus  rich  in 
laccase.  A  little  of  this  is  filtered  through  cotton  wool  when  re- 
quired. On  adding  2  drops  of  this  to  2  Cc.  of  a  1 : 1,000  solution  of 
pyrocatechol,  then  5  drops  of  the  starch  solution,  followed  by  1  to 
3  drops  of  a  6:  100  solution  of  acetic  acid,  an  intense  blue  color  is 
gradually  produced.  On  repeating  the  test  with  a  similar  solution 
of  hydroquinone  no  reaction  occurs.  But,  on  substituting  a  4.9:  100 
solution  of  sulphuric  acid  for  the  acetic  acid,  a  blue  color  will  grad- 
ually appear.  With  resorcinol,  under  similar  conditions,  a  nega- 
tive reaction  is  obtained  with  either  acid.  The  reaction,  therefore, 
serves  easily  to  distinguish  these  three  isomeric  diphenols.  (J. 
Wolff,  Annates  de  Chim.  Analyt.,  1917,  22,  105,  through  The  Phar- 
maceutical Journal  and  Pharmacist.) 
The  Chemical  Structure  of  Nucleic  Acid. — The  bustle  of  a 
busy  world,  particularly  in  war  time,  is  likely  to  leave  us  oblivious 
