THE  AMERICAN 
JOURNAL  OF  PHARMACY, 
DECEMBER,  1878. 
LABORATORY  NOTES. 
By  Albrrt  B.  Prescott. 
I.  Scheme  for  the  Valuation  of  Dover's  Powder,  with  Analysis 
of  Six  Samples. 
The  samples  were  purchased  in  Ann  Arbor,  Massillon,  O.,  and 
Dalton,  O.  The  process  was  as  follows  :  The  powders  were  made 
alkaline  and  agitated  with  several  portions  of  benzole.  The  emetia 
and  narcotina  are  dissolved,  the  morphia  is  not  dissolved  (more  than  a 
trace),  from  alkaline  solutions  by  benzole.1  The  benzole  solution  was 
concentrated,  and  the  alkaloids  extracted  with  acidulated  (sulphuric 
acid)  water  ;  this  solution  was  made  slightly  alkaline  with  ammonia, 
and  agitated  with  several  portions  of  petroleum  naphtha  (sp.  gr.  '725). 
Petroleum  naphtha  dissolves  emetia  and  only  a  trace  of  narcotina.2 
The  petroleum  naphtha  was  concentrated,  and  treated  with  acidulated 
(sulphuric  acid)  water.  The  acidulated  water  solution  was  treated 
with  Mayer's  solution,  1  cc.  of  which  precipitates  0*0189  gram  emetia.3 
The  alkaline  solution,  after  agitating  with  petroleum  naphtha,  was  made 
slightly  acid  (sulphuric)  and  titrated  with  Mayer's  solution,  1  cc.  pre- 
cipitating '0213  gram  narcotina.4  The  residue,  after  treating  the  pow- 
der with  benzole,  was  treated  several  times  with  amylic  alcohol,  filtered 
and  the  filtrate  evaporated  to  dryness  and  weighed  as  crude  morphia. 
This  was  then  redissolved  in  acidulated  (sulphuric)  water,  filtered  and 
the  filtrate  titrated  with  Mayer's  solution,  1  cc.  precipitating  *020 
grams  morphia. 
The  method  may  be  tabulated : 
1  DragendorfPs  scheme,  in  Prescott's  "Prox.  Org.  Anal.,"  p.  136. 
'  Ibid.    Also  Dragendorff :  "  Ermittelung  von  Giften,"  p.  300. 
'Dragendorff:  "  Werthbestimmung  starkwirkender  Droguen,"  p.  37. 
4  Dragendorff:  "  Werthbestim.,"  etc.,  p. 87  ;  "  Proc.  Am.  Pharm.  Ass  j'1  x,p  238. 
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