53§  Valuation  of  Drugs  and  Foods.  {A^vSefhim' 
(d)  Gelsemtum  (containing  0-35  per  cent,  of  alkaloids). —  1  000 
gramme  of  the  finely  powdered  gelsemium  is  mixed  with  10  ex.  of 
a  modified  Prollius  fluid  and  allowed  to  macerate  for  from  four  to 
twenty-four  hours.  The  solution  is  filtered  and  treated  with  5  c.c 
of  a  dilute  sulphuric  acid  and  5  c.c.  of  water,  as  in  previous  experi- 
ments. A  few  drops  of  this  separated  solution  (1  drop  ==  0-0000175, 
gramme  alkaloids),  containing  the  alkaloids,  are  treated  with  the  fol- 
lowing reagents,  causing  the  reactions  noted  : 
(1)  Mayer's  reagent  produces  an  immediate  yellow  precipitate. 
(2)  Ammonium  molybdate  produces  a  blue-colored  solution 
which  becomes  more  marked  in  a  few  minutes  and  the  color  may 
last  for  a  number  of  hours. 
(3)  Picric  acid  produces  a  slight  yellowish  precipitate. 
(4)  KI  -f-  I  solution  gives  an  orange-brown  colored  precipitate. 
(e)  Opium  (containing  15  per  cent,  of  morphine). — 0-IOO  gramme 
of  powdered  opium  is  mixed  with  about  3  to  5  ex.  of  a  modified  Prol- 
lius fluid  ;  filtered  and  treated  with  5  c.c.  of  a  dilute  sulphuric  acid 
solution,  as  in  the  other  drugs  mentioned.  The  solution  is  nearly 
neutralized  with  5  c.c.  ammonia  water  (dil.).  A  few  drops  of  this 
solution  (1  drop  =  -0000/5  gramme  of  morphine)  give  with  (1)  KI 
-f-  I  solution,  a  brownish-orange-colored  precipitate,  and  with  (2) 
Mayer's  reagent,  a  yellow  precipitate.  (3)  If  a  few  drops  of  the  solu- 
tion are  evaporated  to  dryness  on  a  water-bath,  and  then  a  drop  of 
HNO3  added,  a  deep  brownish-red  color  is  produced. 
(/)  Belladonna  Folia  (containing  0-40  per  cent,  of  alkaloids). —  One 
gramme  of  the  powdered  belladonna  leaves  is  digested  with  10- 
c.c.  of  a  modified  Prollius  fluid,  as  in  the  other  drugs  already  men- 
tioned ;  the  solution  filtered  and  mixed  with  5  ex.  of  a  dilute  sul- 
phuric acid  solution  and  5  c.c.  of  H20.  The  latter  solution  (1  drop 
=  000020  gramme  of  alkaloids)  containing  the  alkaloids  is  separa- 
ted and  a  few  drops  are  mixed  on  a  watch-crystal  with  the  following 
reagents,  which  give  characteristic  alkaloida)  precipitates:  (1)  May- 
er's reagent  produces  a  pronounced  whitish  precipitate  ;  (2)  tannin 
solution  gives  a  slight  yellowish  precipitate  ;  (3)  KI  -j-  1  solution 
gives  at  first  an  orange-brown  precipitate, which  soon  changes  to  a 
greenish  color. 
(g)  StropJiantJius. — One  gramme  of  ground  strophanthus  is 
mixed  with  10  c.c.  of  a  modified  Prollius  fluid,  and  after  maceration 
from  four  to  twenty-four  hours  with  frequent  agitation,  filtered  into  a 
