.Am.  Jour.  Pharm.  \ 
November,  1899.  / 
Valuation  of  Drugs  and  Foods. 
537 
Two  or  three  drops  of  this  solution  on  a  watch-crystal  give 
with : 
(1)  Mayer's  reagent,  a  pronounced  white  precipitate. 
(2)  K2Mn208  -f  H2S04,  a  purple  color  that  is  evanescent. 
(3)  K2Cr207  -j-  H2S04,  a  purple  color  that  is  more  persistent. 
(4)  Gold  chloride  solution  gives  a  very  slight  yellow  precipitate. 
(b)  Guarana. —  I'OOO  gramme  of  the  finely  powdered  guarana  is 
mixed  with  10  c.c.  of  a  modified  Prollius  solution  and  allowed  to 
macerate  from  four  to  twenty-four  hours.  The  solution  is  then  fil- 
tered into  a  small  separatory  funnel  and  5  c.c.  of  a  dilute  sulphuric 
acid  (0-5  per  cent.)  solution  are  added.  The  aqueous  solution  is  sep- 
arated and  a  few  drops  of  this  latter  solution  containing  the 
alkaloids  give,  with  a  tannin  solution,  a  white  precipitate  which 
readily  dissolves  in  excess  of  the  reagent.  A  few  drops  of  the 
solution,  after  neutralizing  with  ammonia,  are  evaporated  nearly 
to  dryness  in  a  watch-crystal  on  a  water-bath.  A  drop  of  HC1 
and  a  very  small  crys'tal  (or  better,  a  drop  of  a  weak  solution)  of 
KCIO3  are  added  to  this  residue ;  this  is  again  evaporated  to  dry- 
ness, and  on  exposing  the  dried  and  cooled  residue  to  the 
fumes  of  NH4OH,  a  faint  opalescent  blue  color  is  produced.  If, 
instead  of  employing  HC1  and  KC103,  as  in  the  previous  test,  a  few 
drops  of  bromine  are  added,  the  solution  evaporated  to  dryness  and 
the  residue  exposed  to  fumes  of  NH4OH,  a  more  pronounced  bluish 
opalescent  color  is  produced. 
(c)  Ipecac  (containing  2-00  per  cent,  of  alkaloids). — One  gramme  of 
the  powder  is  mixed  with  10  c.c.  of  a  modified  Prollius  solution 
and  allowed  to  macerate,  with  frequent  shaking  of  the  bottle  con- 
taining the  mixture,  from  four  to  twenty-four  hours.  The  solution 
is  then  filtered  into  a  small  separatory  funnel  and  5  c.c.  of  a  dilute 
sulphuric  acid  solution  (0-5  per  cent.)  are  added.  The  latter  solution 
containing  the  alkaloids  is  separated  and  5  c.c.  of  water  are 
added. 
This  solution  (—  200  minims)  contains  approximately  0-02  gramme 
of  alkaloids.  One  minim  contains  o-OOOi  gramme  of  alkaloids. 
To  a  few  drops  of  this  solution  the  following  reagents  are  added 
and  the  precipitates  noticed  : 
(1 )  Mayer's  reagent  gives  a  copious  yellowish-white  precipitate. 
(2)  K2Cr207  solution  gives  a  copious  pumpkin-yellow  precipitate. 
(3)  Picric  acid  produces  a  bright  yellow  precipitate. 
