62  Frcehdes  Reagent  a  Test  for  Morphia.  {Am'^r\^6arm' 
standing).  In  the  hand-books,  Fresenius,*  Otto,f  Wormley,J  Heppe,§ 
and  others,  agree  in  this, — Wittstein,  on  the  other  hand,  giving  as 
result  a  yellowish  coloration. ||  Hager^[  and  Heppe,  (as  just  quoted) — 
both  as  compilers — state  that,  by  heating  the  sulphuric  acid  solution  to 
100°  to  1500  C,  a  "faint  violet-red"  or  "  red  "  color  is  obtained. 
A  trace  of  nitric  with  sulphuric  acid  greatly  effects  its  reaction  with 
morphia, — a  mixture  of  the  two  acids  furnishing  a  much  more  delicate 
test  for  that  alkaloid  than  nitric  acid  alone.  In  1861,  Erdmann,  dur- 
ing some  fruitful  researches  in  the  identification  of  alkaloids**  fixed 
upon  a  mixture  containing  little  more  than  one  hundredth  of  one  per 
cent,  of  nitric  acid  of  spec.  grav.  1*25, ft  referred  to  as  Erdmann's  re- 
agent giving  with  morphia  a  violet  color.  Now  how  minute  a  trace  of 
nitric  acid  will  enable  sulphuric  acid  to  color  notable  quantities  of 
morphia  reddish,  I  do  not  know.  As  to  the  purity  of  the  "  chemically 
pure  "  sulphuric  acid  of  the  market,  most  analysts  find  occasionally  lots 
which  reveal  nitric  acid,  even  by  the  ferrous  sulphate  test,  and,  still 
more  often,  the  brucia  test  or  the  anilin  sulphate  test  shows  the  im- 
purity, jj    Query  :  how  does  the  delicacy  of  a  morphia  test  for  nitric 
"  Qual.  Chem.  Anal.,"  Johnson's  Edition  from  14th  German,  (1875),  p.  392. 
t  "  Detection  of  Poisons,"  New  York,  1862,  p.  146. 
%  "  Micro-Chemistry  of  Poisons,"  (1869),  "  Tabular  View." 
>/.  "Die  Chemischen  Reactionen,"  Leipzig,  1875,  P«  24^- 
||  "Analyse  v.  Pflanzen  u.  Pflanzentheilen,"  1868,  p  156. 
\  "  Untersuchungen,"  ii,  161. 
**  "  Annal  d.  Chemie  u.  Pharm.,"  Bd.  120,  p.  188.  "  Zeitsch.  f.  analyt.  Chemie," 
i,  224, — (Neubauer's  Report). 
ff  Six  drops  of  nitric  acid  of  sp.  gr.  1*25  are  mixed  with  100  c.  c.  water,  and  ten 
drops  of  this  mixture  are  mixed  with  20  grams  concentrated  sulphuric  acid.  Ot 
this  reagent,  8  to  20  drops  are  added  to  1  or  2  milligrams  of  the  solid  to  be  tested, 
and  after  \  to  \  hour  the  color  is  noted.  The  heat  developed  by  a  drop  or  two  of 
water  increases  the  delicacy  of  the  reaction — a  violet  color.  Erdmann  reported 
color  tests  by  this  reagent  with  four  other  alkaloids,  viz. :  narcotina,  strychnia, 
brucia  and  veratria. 
Shortly  after  the  introduction  of  Erdmann's  reagent,  Husemann  ("  Annal.  d. 
Chem.  u.  Pharm.,"  Bd.  128,  p.  303)  ascertained,  that  if  the  sulphuric  acid  solution 
of  morphia  (colorless,  he  states,  in  the  cold)  be  heated  above  ioo°  C.  but  not  as  high 
as  1500  C,  and  then  treated  with  a  few  drops  of  nitric  acid  of  sp.  gr.  1*2,  a  dark 
violet  color  will  give  evidence  of  morphia,  the  test  being  more  delicate  than  Erd- 
mann's, revealing  0*00001  gram  alkaloid.  This  test  of  Husemann  is  given  in  the 
recent  manuals  of  Fresenius,  Hager  and  Heppe. 
%  %  Bedford  :  "  Proc.  Am.  Phar.  Asso.,"  1874,  429.  Dickinson:  (Contribu- 
tions Chem.  Lab.  Univ.  Mich.)  "Am.  Chemist,"  1875,  Aug.,  p.  43. 
