ANovembe?S'}     Alkaloids  and  Alkaloidal  Drugs.  517 
For  the  estimation  of  the  additive  iodine  the  periodide  was  dis- 
solved in  chloroform  mixed  with  alcohol  and  titrated  with  standard- 
ized thiosulphate,  using  starch  as  indicator.  It  is  best  to  add  first 
an  excess  of  the  thiosulphate  solution,  then  add  considerable  water, 
when  the  excess  is  titrated  back  with  standardized  iodine.  For  the 
total  iodine  the  periodide  is  dissolved  in  a  little  chloroform  mixed 
with  a  few  drops  of  alcohol ;  powdered  zinc  is  then  added  and  the 
mixture  kept  on  a  water-bath  till  effervescence  (from  the  action  of 
zinc  on  the  chloroform)  ceases.  To  the  mixture,  when  cold,  ammo- 
nia water  is  added,  and  the  iodine  in  the  zinc  and  ammonium  iodide 
is  estimated  exactly  as  described  in  the  analysis  of  morphine  tetrai- 
odide.1 
F'or  additive  iodine,  0-1492  gramme  of  the  periodide  gave 
0-0880045  gramme  iodine,  and  0-122  gramme  gave  00727250 
gramme  iodine. 
Calculated  for 
C28H40N2O5.HI.I7.  Found. 
<  >  • '  *  •  •  •  •  59'24  59 '98 
2   .   ......   59-24  59-61 
For  total  iodine,  0-1313  gramme  of  the  periodide  gave  0-0890502 
gramme  iodine,  and  0-12095  gramme  gave  00818797  gramme 
iodine. 
Calculated  for 
C2sH40N2O5.HI.I7.  Found. 
I   67*69  67-82. 
2  67-69  67-69 
From  these  results  we  draw  the  provisional  iodine  factor  of  the 
alkaloids  of  ipecacuanha,  i-co  of  iodine  =  0-55  of  alkaloids. 
PERIODIDES  OF  HYDRASTINE." 
The  higher  periodide  is  of  a  very  dark  brown  color,  very  diffi- 
cultly soluble  in  ether,  benzol  or  cold  chloroform,  more  easily  in 
hot  chloroform  and  in  alcohol,  and  very  easily  in  a  mixture  of 
alcohol  and  chloroform,  or  alcohol  and  ether.  It  melts  in  hot 
water.  Attempts  to  crystallize  it  failed.  It  is  obtained  when  the 
dilute  alkaloid  solution  is  slowly  added  to  a  large  excess  of  iodine 
dissolved  with  potassium  iodide  in  water.    So  made,  it  is  constant 
_ 
1  "  Proc.  Am.  Pharm.  Assoc.,"  1897,  p.  340,  et.  seq. 
2  This  body  was  reported  upon  in  full  in  an  article  in  Am.  Jour.  Pharm., 
71,  257  (1899). 
