264 
Hydrastine  Hexiodide. 
Am.  Jour.  Pliarm. 
June,  1899. 
the  hydrastine  is  shaken  out  with  ether  and  ammonia,  the  ether 
poured  into  a  tared  beaker  and  slowly  evaporated  in  a  dark  place. 
After  drying  in  vacuum  over  sulphuric  acid  and  paraffine  the  beaker 
is  weighed.  The  hydrastine  is  left  in  perfectly  white  crystals,  and 
only  a  slightly  yellowish  tint  can  be  seen  on  the  sides  of  the  beaker. 
This  tint  is  probably  due  to  traces  of  canadine,  which  becomes 
yellow1  on  exposure  to  light.  Of  course,  instead  of  shaking  out,  the 
method  of  perforation"  may  be  used  if  preferred. 
For  the  estimation  of  berberine  a  current  of  dry  air  is  passed 
through  the  Soxhlet  till  all  the  ether  is  removed,  the  Soxhlet  con- 
nected with  an  Erlenmeyer  containing  40  or  50  c.c.  of  alcohol, 
and  the  extraction  continued  tili  the  alcohol  comes  out  colorless. 
The'alcoholic  extract  containing  the  berberine,  and  considerable 
quantities  of  extractive  matter,  is  poured  out  into  an  evaporating 
dish,  the  Erlenmeyer  washed  out  with  hot  water  and  a  little  dilute 
acetic  acid,  the  washings  added  to  the  evaporating  dish,  and  the 
latter  kept  on  a  water-bath,  adding  water  from  time  to  time  till  all 
the  alcohol  has  disappeared.  A  little  more  diluted  acetic  acid  is 
now  added,  the  dish  covered,  and  when  completely  cold  its  contents 
are  filtered  into  an  Erlenmeyer  having  the  capacity  of  about  300 
or  400  c.c.2 
Six  to  8  c.c.  of  acetone  are  added  to  the  contents  of  the  Erlen- 
meyer, to  which  the  washings  of  the  dish  and  the  filter  have  been 
added,  and  then  a  10  per  cent,  solution  of  sodium  hydrate  is  added, 
drop  by  drop,  till  the  precipitate  first  formed  ceases  to  disappear  on 
shaking,  and  the  liquid  acquires  a  strongly  alkaline  reaction.  The 
Erlenmeyer  is  then  stoppered  and  shaken  in  circular  direction  for 
about  ten  or  fifteen  minutes,  and  then  set  aside  in  a  cool  place  for 
two  or  three  hours.  The  berberine-acetone  separates  out  in  crystals, 
some  of  which  adhere  to  the  sides  of  the  vessel.    The  supernatant 
1  E.  Schmidt,  1894:  Arch.  d.  Pharm.,  232,  141. 
2  In  the  remaining  procedure,  the  simplest  way  would  be  to  precipitate  the 
berberine  with  hydrochloric  or  nitric  acid,  but  in  this  case  a  considerable 
amount  of  extractive  matter  contaminates  the  precipitate,  and  the  estimation 
would  fall  out  too  high,  though  the  error  in  this  respect  might  be  compensated 
to  some  extent  by  the  solubility  of  the  hydrochloride  or  nitrate  in  water.  But 
the  best  way  is  to  purify  the  berberine  by  converting  it  into  berberine-acetone, 
regenerate  the  alkaloid  by  means  of  sulphuric  acid,  and  then  estimate  it  volu- 
metrically  by  standard  potassium  iodide. 
