212 
Estimation  of  Picric  Acid. 
{Am.  Jo«r.  Pharm. 
\      April,  1884. 
The  Dame  I  propose  for  this  substance  is  jambosin.  Therapeutically 
it  is  of  very  little  interest,  as  I  have  taken  several  doses  without  any 
apparent  effect.  The  active  principle  of  jambosa  is  no  doubt  to  be 
found  in  the  oleoresin,  which  is  a  powerful  sialagogue,  and  deserving 
of  further  research. — Pharm,  Jour,  and  Trans.,  March,  1884. 
DETECTION  AND  ESTIMATION  OF  TRINITROPHENOL 
(PICRIC  ACID). 
By  G.  Christel. 
This  paper  contains  an  examination  of  the  principal  reactions  of 
trinitrophenol  made  with  a  view  to  its  qualitative  detection  and  quan- 
titative estimation.  The  aqueous  solution  of  picric  acid  is  not  precipi- 
tated by  neutral  solutions  of  lead  or  copper  salts  ;  neither  is  ammonium 
picrate,  unless  the  solution  is  alkaline,  when  lead  acetate  gives  a  reddish 
yellow  precipitate  and  copper  sulphate  a  yellowish  green  precipitate  in 
dilute  solutions,  and  a  bright  green  in  concentrated  solutions.  A  solu- 
tion containing  half  a  milligram  of  picric  acid  in  5  cc.  of  water  is  not 
at  once  precipitated  by  a  solution  of  cuprammonium  sulphate,  but  on 
standing  for  24  hours  a  distinct  precipitate  is  obtained,  which  is 
insoluble  in  ammonia,  but  is  decomposed  by  water.  Solution  of  basic 
lead  acetate  is  a  very  delicate  test  for  picric  acid,  yielding  a  bright 
yellow  precipitate.  A  solution  containing  the  tenth  of  a  milligram  of 
picric  acid  in  5  cc.  of  water,  gives  after  12  hours  a  distinct  precipitate, 
and  a  solution  containing  the  twentieth  of  a  milligram  in  5  cc.  of 
water  a  strong  opalescence,  which  subsequently  forms  a  distinct  sedi- 
ment. When  this  sediment  is  decomposed  by  the  addition  of  1  drop 
of  sulphuric  acid,  and  the  solution  is  rendered  alkaline  with  ammonium 
hydrale  and  evaporated  to  dryness,  a  residue  is  left  which,  when  dis- 
solved in  a  little  water  and  warmed  with  a  drop  of  potassium  cyanide 
solution,  gives  a  distinct  red  color.  The  yellow  coloring  matters  of 
the  bark  of  Quercus  tinctoria  (quercitron),  and  the  root  of  Broussonetia 
tinctoria  also  give  precipitates  with  basic  and  neutral  lead  acetate,  but 
the  precipitates  do  not  give  the  reaction  with  potassium  cyanide  when 
treated  as  above  described.  An  aqueous  solution  of  methyl  green  pre- 
cipitates solutions  of  picric  acid.  The  green  precipitate  dissolves  in 
ammonia,  forming  a  deep  yellow  solution,  which  is  precipitated  by 
basic  lead  acetate,  and  this  precipitate  gives  the  reaction  with  potassium 
