■'ANoVJember?i89™'}     Alkaloids  and  Alkaloidal  Drugs.  521 
through,  and,  by  means  of  the  wash  bottle, the  precipitate  is  returned 
to  the  same  Erlenmeyer  in  which  the  precipitation  took  place. 
In  this  way  all  loss  is  avoided.  To  the  precipitate  about  4  or  5  c.c. 
of  a  5  per  cent,  solution  of  sulphuric  acid  is  now  added,  and  then 
water  enough  to  make  about  100  or  200  c.c.  The  Erlenmeyer  is 
now  put  into  hot  water,  when  the  precipitate  will  completely  dis- 
solve in  the  course  of  a  few  minutes.  The  solution  is  now  poured 
into  a  long-necked  flask,  washing  the  Erlenmeyer  several  times,  the 
flask  put  on  an  asbestos  plate  and  kept  very  gently  boiling  for  about 
an  hour  and  a  half  or  two  hours,  adding  hot  water  from  time  to 
time  if  necessary. 
The  flask  is  now  cooled  and  its  contents  poured  out  into  a  litre 
measuring  flask,1  into  which  there  has  been  previously  taken  from 
a  burette  100  c.c.  of  twentieth  normal  potassium  iodide.  The  flask 
is  washed  several  times,  the  washings  added  to  the  measuring  flask, 
and  the  latter  filled  up  to  1,000  c,c.  and  set  aside  over  night.  500 
c.c.  are  now  filtered  off' into  another  litre  flask,  50  c.c.  of  twentieth  nor- 
mal silver  nitrate  and  nitric  acid  are  added  to  the  flask,  which  is  filled 
up  to  1,000  c.c,  well  shaken,  filtered,  and  5  00  c.c.  of  the  filtered  liquid 
titrated  back  with  fortieth  normal  ammonia  sulphocyanate,  using 
ferric  alum  as  indicator.  Twice  the  number  of  cubic  centimetres  of 
the  sulphocyanate  solution  used  is  equal  to  the  number  of  cubic 
centimetres  of  the  potassium  iodide  solution  consumed  by  the  ber- 
berine,  representing  10  grammes  of  the  hydrastis.  root.  By  multi- 
plying the  number  of  cubic  centimetres  of  twentieth  normal  potas- 
sium iodide  consumed  by  0-167125,  the  percentage  of  anhydrous 
berberine  in  the  root  is  obtained,  as  1  c.c.  of  the  potassium  iodide 
solution  is  equal  to  0*0167125  of  berberine. 
In  our  assay  of  Hydrastis  canadensis  three  samples  of  powdered 
hydrastis  were  treated  in  the  way  described.  The  berberine  was 
estimated  volumetrically,  the  hydrastine  both  iodometrically  and 
gravimetrically. 
For  Hydrastine. 
Iodine  Consumed  Hydrastine. 
by  2  Grammes  of  the  Root.  lodometric.  Gravimetric. 
I  0*0760015  2*29  2*29 
2  .  .  .  0*0772012  2*33  2*30 
3  0*0777770  2*35  2*28 
1  The  berberine  hydriodide  being  extremely  bulky,  the  error  arising  from  the 
space  occupied  by  the  precipitate  is  reduced  to  a  minimum  by  using  a  large 
flask. 
