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Syr  up  of  Hydr  iodic  Acid. 
( A.m.  Jour.  Pharrn. 
t      March,  1899. 
of  the  syrup  taking  place  in  the  hands  of  the  patient.  Retail  phar- 
macists are  well  acquainted  with  the  popular  suspicions  in  such 
instances. 
DESCRIPTION. 
The  descriptive  features,  as  presented  by  the  Pharmacopoeia,  are 
open  to  criticism  as  well  as  improvement. 
The  official  description  is  as  follows  :  A  transparent,  colorless  or 
not  more  than  pale  straw  colored  liquid,  odorless  and  having  a  sweet, 
acidulous  taste. 
After  stating  the  identity  test  with  starch  paste  and  chlorine 
water,  the  following  is  demanded:  Not  more  than  a  faint  bluish  tint 
should  be  produced  in  the  syrup  by  starch  T.  S.  alone  (limit  of  free 
iodine). 
In  a  number  of  examinations  of  colored  specimens  the  writer 
found  free  iodine  in  no  instance. 
The  discoloration  may  be  artificially  produced  by  heating  the 
syrup,  and  a  perfectly  colorless  specimen  may  thus  be  turned  reddish 
brown  in  ten  to  fifteen  minutes,  with  no  evidence  of  free  iodine  on 
cooling. 
The  statement  that  colored  syrups  of  hydriodic  acid  may  be 
restored  by  heating  is  not  substantiated.  On  the  contrary,  they 
turn  still  darker. 
Colored  syrups  do  not  lose  their  effect  and  determinations  show 
that  the  percentage  of  hydriodic  acid  remains  constant.  A  num- 
ber of  examinations  revealed  the  fact  that  syrups,  both  at  the  time 
of  preparation  and  after  discoloration,  show  identical  percentages. 
RESTORATION. 
Of  considerable  importance  to  the  pharmacist  is  the  restoration 
of  the  discolored  syrup  to  its  original  condition. 
This  may  be  accomplished  by  means  of  animal  charcoal,  as 
pointed  out  by  Mr.  O.  A.  Rouillon. 
Purified  animal  charcoal  must  be  employed,  as  commercial  bone- 
black  contains  phosphates,  which  dissolve  in  the  acid. 
To  determine  if  animal  charcoal  also  has  the  power  of  absorbing 
hydriodic  acid,  a  number  of  specimens  of  the  syrup  were  examined 
as  to  their  acid  percentage  before  and  after  decolorization. 
In  all  cases  no  loss  of  acid  was  found,  and  restoration  of  the  dis- 
colored syrup  by  these  means  is  perfectly  legitimate. 
