Am.  Jour.  Pharm. 
June,  1890. 
Hydrastine  Hexiodidc. 
265 
liquid  is  then  poured  on  a  small  filter,  the  precipitate  washed  once 
or  twice  by  decantation,  and  then  on  the  filter  till  the  washings  are 
colorless.  The  filter  is  then  pierced  through,  and  by  means  of  the 
spritz  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  sul- 
phuric 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  dissolve  in  the  course  of  a  few  minutes. 
The  solution  is  now  poured  out  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  iod  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  twen- 
tieth normal  silver  nitrate,  and  nitric  acid  added  to  the  flask,  which 
is  filled  up  to  1,000  c.c,  well  shaken,  filtered  and  500  c.c.  of  the 
filtered  liquid  titrated  back  with  fortieth  normal  ammonium  sulpho- 
cyanate,  using  ferric  alum  as  indicator.  Twice  the  number  of  cubic 
centimetres  of  the  sulphocyanate  solution  used  is  equal  to  the  num- 
ber of  cubic  centimetres  of  the  potassium  iodide  solution  consumed 
by  the  berberine,  representing  10  grammes  of  the  hydrastis  root. 
By  multiplying  the  number  of  cubic  centimetres  of  twentieth  nor- 
mal potassium  iodide  consumed  by  0-167125,  the  percentage  of 
anhydrous  berberine  in  the  root  is  obtained,  as  1  c.c.  of  the  potas- 
sium 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. 
^he  berberine  hydriodi.de  being  extremely  bulky,  the  error  arising  from  the 
space  occupied  by  the  precipitate  is  reduced  to  a  minimum  by  using  a  large 
flask. 
