462 
Blue  Iodide  of  Starch. 
Am.  Jour.  Pharm. 
Sept,,  1887. 
solution 7  useful  for  application  either  by  the  spray  or  brush.  The 
ether  quickly  evaporating  leaves  the  powder  in  situ.  It  is  useful  for 
naso-pharyngeal  atrophic  conditions. 
4.  lodol,  1  drachm;  glycerin,  1  drachm-,  vaseline,  7  drachms. — This 
is  a  modification  of  one  of  Rumbold's  sprays.  It  is  a  very  soothing 
application  for  pharyngeal  conditions.  It  requires  to  be  warmed  before 
using. 
5.  lodol  pastilles. — Iodol,  1  grain  •  glycerin,  1  minim ;  glycogela- 
tin,  18  grains.  These  are  very  useful  for  chronic  pharyngeal  condi- 
tions, and  are  much  preferable  to  iodoform  pastilles. 
6.  lodol  bougies,  containing  J  a  grain  iodol  in  each.  These  are 
made  for  use  in  diseased  nasal  conditions. 
7.  lodol  wool,  10  per  cent.,  for  tampons,  etc. 
8.  Iodol  gauze  for  dressings. — Medical  News,  July  16. 
BLUE  IODIDE  OF  STARCH.1 
By  F.  Mylius. 
The  analogy  between  iodide  of  starch  and  iodocholic  acid,  is  shown 
by  the  following  facts:  (1)  Iodine  solutions  which  color  starch  contain 
either  hydriodic  acid  or  one  of  its  salts ;  (2)  the  presence  of  substances, 
such  as  chlorine,  which  decompose  hydriodic  acid,  prevents  the  for- 
mation of  iodide  of  starch ;  (3)  silver  solutions  decolorize  solution 
of  iodide  of  starch  —  the  color  is  restored  by  adding  potassium 
or  hydrogen  iodide;  (4)  an  aqueous  solution  of  iodine  cannot  color 
starch  blue ;  the  blue  color  appears  at  once  when  a  trace  of  hydriodic 
acid  or  potassium  iodide  is  added. 
When  starch  is  added  to  a  solution  of  iodine  and  hydriodic  acid 
containing  sulphuric  acid,  iodide  of  starch  separates :  the  amount  of 
iodine  and  hydriodic  acid  which  has  been  absorbed  by  the  starch  can 
be  readily  determined  by  titration.  The  results  of  several  experiments 
show  that  the  proportion  of  iodine  absorbed  to  that  of  the  hydriodic 
acid  is  4:  1,  and  it  is  probable  that  the  resulting  compound  has  the 
formula  (C24H40O20I)4,  HI.  From  this,  the  author  concludes  that  the 
formula  of  starch  is  C24H40O20,  which  is  that  ascribed  to  it  by  Pfeiffer 
and  Tollens  (1882). 
Iodide  of  starch  dried  in  a  vacuum  appears  to  be  anhydrous.  The 
1Ber.,  xx.,  688-695;  reprinted  from  Jour.  Chem.  Soc,  June,  p.  568. 
