358  Contributions  from  the  School  of  Pharmacy ,  etc.  {A%^3^m 
II.  Comparison  of  four  Processes  for  the  Morphiometric  Assay  of  Opium.  By  James- 
Lynn,  Ph.C. 
Four  samples  of  opium,  obtained  at  different  reputable  pharmacies,, 
were  each  assayed  by  the  four  processes.  The  opium  was  dried,  to 
lose  no  more  weight,  at  ioo°C. 
PERCENTAGES  OBTAINED. 
No.  i. 
No.  2. 
No.  3. 
No.  4 
I. 
Procter's  Staples'  process,1 
I  1*22 
13-62 
9-14 
12  69 
2. 
Mohr's  process,2 
1 1  *40 
13-48 
9*3° 
I2.77 
3- 
Hager's  Jacobson's  process,3 
n-68 
13-86 
9-46 
12-98 
4- 
Dragendorff's  Mayer's  process,4 
i2'33 
14-00 
10-40 
13-06 
Of  the  three  gravimetric  methods,  Staples'  gives  much  the  purest  and 
best  crystallized  morphia,  being  nearly  colorless  and  readily  detached 
and  gathered.  For  this  reason  Staples'  is  preferred  by  the  operator  to 
Mohr's  or  Hager's  method,  unless  time  is  an  important  object.  Hager's 
is  the  quickest  and  simplest,  being  completed  in  four  to  six  hours,, 
while  the  product  is  about  as  pure  as  Mohr's  ;  the  crystals  from  both 
these  methods  being  imperfect  and  colored.  The  yield  is  greater  in 
Hager's  than  in  Staples'  process,  but  very  likely  the  amount  of  absolute 
morphia  is  not  much  greater. 
In  any  gravimetric  method  the  morphia  separates  by  crystallization 
slowly,  and,  we  must  suppose,  approximately,  and  that  a  weighable 
luProc.  Am.  Phar.  Asso.,"  1870,  p.  129;  "Am.  Jour.  Phar.,"  1871,  p.  65. 
(First  method  given  by  Procter.)    The  plan  of  the  U.  S.  P.  preparation  of  morphia.- 
2"Annal.  der  Chem.  u.  Phar.,"  B.  35,  S.  1205  "  U.  S.  Dispensatory." 
Third  method  given  by  Procter,  as  above  quoted. 
3  "Hager's  Untersuchungen,"  II,  1765  "Am.  Jour.  Phar.,"  1871,  p.  224 
Founded  on  Mohr's. 
The  Voli  metric  Method.  Mayer,  "Am.  Jour.  Phar.,"  1863,  p.  20;  Dragen- 
dorfF,  "  Werthbestimmung  starkwirkender  Droguen,"  p.  86.  This  method  was- 
employed  as  follows :  Three  grams  dried  powdered  opium  were  exhausted  with 
benzene,  the  adhering  benzene  fully  evaporated,  the  dry  powder  macerated  in  water 
for  12  hours,  then  percolated  on  a  filter  with  water  until  the  water  passed  colorless. 
The  dilute  percolate  acidulated  with  sulphuric  acid,  and  the  reagent  added  from 
the  burette  in  portions  so  limited  as  to  prevent  excess,  allowing  the  precipitate  to 
subside  after  each  addition.  At  intervals,  a  drop  of  the  clear  supernatant  liquid  is 
taken  on  a  dark-colored  glass  slide,  with  a  drop  of  reagent  from  the  burette,  this 
portion  being  rinsed  into  the  tested  solution  each  time  until  the  addition  is  com- 
pleted. Each  c.c.  of  a  solution  of  13*546  grams  mercuric  chloride  and  49*8  grams 
potassium  iodide  in  water  to  one  litre,  precipitates  o'02  grams  morphia. 
