266  Hydras  tine  Hexiodide.  {Amju°no899arm* 
For  Hydrastine. 
Iodine  consumed 
by  2  grammes  of  Hydrastine. 
the  root.  lodomettic.  Gravimetric. 
1    0*0760015  2*29  2*29 
2   o"0772oi2  2*33  2*30 
3    0-0777770  2-35  2-28 
For  Berberine. 
Number  of  c.c.  of 
N 
—  KI  consumed  by 
10  grammes  of  the  Berberine, 
root.  anhydrous. 
I   .  15*1  2-52 
2   I5-3  2-55 
3  '•  14*8  2-47 
With  regard  to  the  precipitation  of  berberine  by  potassium  iodide, 
we  wish  to  draw  attention  to  the  fact  that  even  a  solution  of  the 
free  alkaloid  without  any  addition  of  acid  is  precipitated  by  potas- 
sium iodide.  As  there  is  no  acid  to  combine  with  the  potassium, 
the  question  is  what  becomes  of  the  metal  when  the  iodine  of  the 
potassium  iodide  is  taken  up  by  the  berberine  ?  That  there  is  no 
potassium  in  the  precipitated  berberine  hydriodide  was  proven  by 
igniting  the  precipitate  with  sulphuric  acid  and  ammonium  nitrate, 
when  no  trace  of  residue  was  to  be  found.  All  the  potassium 
must  then  pass  into  the  filtrate  and  part  of  it  must  exist  there  as 
a  salt  of  something  acting  as  an  acid,  as  there  is  no  trace  of  alka- 
linity in  the  filtrate.  No  one  of  the  indicators  gives  an  alkaline 
reaction.  We  acidulated  the  filtrate  with  sulphuric  acid,  shook  it 
up  with  ether,  washed  the  ether  till  there  was  no  reaction  given  for 
iodine  by  sodium  nitrite  and  starch,  nor  for  sulphates  by  barium 
chloride,  and  evaporated  the  ether  to  dryness;  a  very  small  amount 
of  a  crystalline  substance  was  left,  which  would  seem  to  indicate 
the  presence  of  an  organic  acid.  But  the  quantity  was  too  small 
for  a  closer  examination.  We  intend  to  take  a  larger  quantity  of 
pure  berberine  into  operation  and  investigate  the  subject  thoroughly 
in  the  near  future. 
University  of  Michigan,  April,  1899. 
