AmFe°buri8P76arm'}  Frcehdes  Reagent  a  Test  for  Morphia.  59 
NOTE  ON  FRCEHDE'S  REAGENT  AS  A  TEST  FOR  MORPHIA. 
BY  ALBERT  B.  PRESCOTT. 
On  page  21  (Jan.  No.)  of  the  present  volume  of  this  Journal,  Mr. 
Wellcome  brings  to  notice  and  refutes  certain  preposterous  claims 
made,  in  St.  Bartholomew's  Hospital  Reports  of  1874,  for  a  saturated 
solution  of  molybdic  acid  in  sulphuric  acid,  as  a  test  for  morphia, 
namely  :  that  this  reagent  distinguishes  traces  of  that  alkaloid,  when  it 
is  directly  applied  to  opium  tinctures,  lozenges  and  other  mixtures.  It 
certainly  should  not  be  taken  as  evidence  of  anything  in  particular,  that 
there  should  be  a  lively  play  of  colors,  when  a  strong  solution  of  molyb- 
dic acid  in  concentrated  sulphuric  acid,  is  brought  upon  aqueous, 
alcoholic  or  saccharine  mixtures  containing  unclassified  organic  matter. 
As  Mr.  Wellcome  well  explains,  a  large  number  of  deoxidizing  agents 
reduce  molybdic  acid  to  blue  compounds  (molybdic  molybdates).  But 
the  experiments  which  Mr.  W.  reports  fail  to  sustain  the  extreme 
scepticism  of  his  conclusion,  that  "  there  is  no  more  need  of  molybdic 
acid  or  molybdates  in  these  test  solutions  than  for  the  presence  of  any 
other  blue  coloring  matter,  which  will  blend  with  the  color  produced 
by  sulphuric  acid,  and  produce  tints  which,  while  pleasing  to  the  eye, 
confuse  the  analyst." 
In  1866,  Froehde  reported*  the  identification  of  morphia  by  the 
reagent  which  bears  his  name — a  fresh  solution  of  five  milligrams  of 
sodium  molybdate  in  one  cubic  centimeter  of  pure  concentrated  sul- 
phuric acid  (1  part  to  368  parts) — a  violet  color  being  obtained. 
In  1868,  Alm£n,  f  after  investigation,  stated  that  Froehde's  test  was 
much  more  certain  and  delicate  than  any  of  the  old  reactions  for  mor- 
phia, except  that  with  iodic  acid,  and  more  characteristic  than  that  by 
sulphuric  with  nitric  acid  (Erdmann's). 
Kauzmann,  in  1869,  found  J  that  0*05  of  a  milligram  of  morphia, 
if  pure  and  solid,  could  be  recognized  by  this  test.  Neubauer,  in  1870, 
found  §  the  test  delicate  and  distinguishing  for  morphia  in  presence  of 
strychnia.    J.  H.  Buckingham, ||  in  1873,   usmg  a  fresh  solution  of  8 
*"Archivder  Pharm.,"  Bd.  126,  p.  54;  "  Zeitschr.  f.  anal.  Chemie,"  v,  214 
"  Proc.  Am.  Phar.  Asso.,"  xv,  241. 
f "  Neues  Jahrbuch  f.  Pharm.,"  Bd.  30,  p.  87.  "  Zcitsch.  f.  anal.  Chem.,,,j 
viii,  77. 
X  "Zeitsch.  f  anal.  Chemie,"  viii,  105. 
$  "  Zeitsch.  f.  anal,  Chemie,"  ix,  241. 
||  "Amer.  Jour.  Phar.,"  xlv,  (1873)  H9  5  "  Polytechn.  Notizblatt  "  (1874),  77  ; 
"  Chem.  Cent."  (1873),  797  >  "Jour.  Chem.  Soc."  (1874),  715  ;  "Zeitsch.  an.  Ch.," 
xiii,  234. 
