422  GLEANINGS  FROM  THE  GERMAN  JOURNALS. 
dissolves  or  exhausts  the  substance  to  be  examined  in  water 
containing  acetic  acid,  and  in  the  acid  liquor  immerses  a  stout 
platina  wire,  carrying  at  its  lower  end  a  piece  of  iron  wire. 
After  one  to  three  hours  immersion,  copper,  if  present,  is  depo- 
sited upon  the  platina  as  a  brownish  coating ;  which  is  then 
removed  to  a  test  tube,  in  which  has  been  placed  four  or  five 
drops  of  pure  nitric  acid  of  20  to  25  per  cent.  The  copper 
thus  dissolved,  may  now  be  made  evident  in  the  solution  by 
its  producing  a  blue  color  with  an  excess  of  caustic  ammonia. 
In  this  way  the  presence  of  this  metal  has  been  detected  in 
solutions  in  which  neither  ammonia  nor  ferrocyanide  of  potas- 
sium gave  any  reaction.  This  method  is  particularly  applicable 
to  vegetable  extracts  and  juices,  in  which,  on  account  of  tannic 
acid  and  similar  matters,  iron  alone  gives  but  doubtful  results. 
— Ph.  Centralhatte.    JV.  Jahrh.  Ph.  xx.  222. 
Detection  of  the  adulteration  of  arrow  root  with  potato  or  corn 
starch. — According  to  J.  F.  Albers,  [Arch.  d.  Pharm.,)  this  is 
effected  with  certainty,  by  means  of  their  behaviour  towards 
hydrochloric  acid.  When  one  part  arrow  root  is  shaken  with 
three  parts  of  a  mixture  of  two  parts  hydrochloric  acid  of  1-12 
sp.  gr.  and  one  part  of  distilled  water,  at  ordinary  temperatures, 
for  about  three  minutes,  no  reaction  is  observable.  But  should 
corn  starch  be  subjected  to  this  treatment,  it  becomes  changed 
into  a  gelatinous,  translucent,  and  finally  into  a  semi-fluid  mass. 
Potato  starch  behaves  in  the  same  way,  with  the  production  of 
an  easily  recognized  and  characteristic  smell. 
If  a  mixture  of  arrow-root  with  one  or  more  of  these  sub- 
stances is  to  be  dealt  with,  the  arrow-root  is  to  be  separated  by 
treating  the  whole  for  two  to  three  hours  with  the  hydrochloric 
acid,  by  which  the  arrow-root  becomes  soluble,  and  may  be 
filtered  from  the  remaining  softish  mass,  which,  when  washed, 
dried  in  the  air,  and  weighed,  shows  by  the  loss  in  weight  the 
amount  of  arrow-root  present.-—  Vurtiljh.  Ph.  xiii.  276. 
Tobacco  Seed  has  been  examined  by  F.  M.  Brandt,  without 
finding  either  propylamia  or  nicotia.  The  latter  alkaloid  was 
discovered  in  the  solid  matter  obtained  by  evaporating  the  aque- 
ous extract,  but  was  believed  to  be  a  product  of  the  decomposi- 
tion of  some  of  the  protein-like  substances.    The  following  are 
