Am'ja0nuyi^9arm'}    Permanent  Syrup  of  Hydriodic  Acid.  15 
especially  as  there  are  now  obtainable  in  the  markets  a  number  of  syr- 
ups of  hydriodic  acid  claimed  to  be  unalterable  on  exposure  to  air. 
Various  preservative  substances  are  used  to  achieve  this  end,  such 
as  honey,  potassium  hypophosphite  and  hypophosphorous  acid ;  gly- 
cerin has  little  or  no  influence  in  retarding  decomposition. 
The  new  National  Formulary  (p.  122)  gives  a  formula  for  the  prep- 
aration of  a  colorless  hydriodic  acid  syrup,  prepared  by  double  decom- 
position between  potassium  iodide  and  tartaric  acid  in  the  original 
way,  but  preserving  it  from  oxidation  with  potassium  hypo-phos- 
phite. 
This  formula,  in  its  practical  workings,  is  most  excellent  and,  in 
the  writer's  opinion,  superior  to  the  pharmacopoeial  process  of  iodine 
and  sulphuretted  hydrogen.  There  is  one  point  in  it,  however,  upon 
which  criticism  might  be  turned  and  that  is  the  presence  of  the  potas- 
sium hypophosphite,  or,  what  is  more  probable,  hypophosphorous 
acid,  since  some  acid  tartrate  of  potassium  still  remains  in  the  finished 
solution  unprecipitated,  but  the  quantity  of  this  salt  used,  is  so  small 
that  this  feature,  practically,  need  not  be  regarded. 
The  writer  has  used  this  formula  since  last  August,  with  but  one 
modification  in  detail,  and  that  was  the  substitution  of  syrupy  glucose 
for  potassium  hypophosphite,  as  the  preservative.  A  sample  of  some 
made  last  August  is  as  clear  and  destitute  of  free  iodine  as  some  made 
yesterday.    The  modified  formula  is  as  follows : 
Iodide  of  Potassium  123  grains. 
Tartaric  Acid  112  " 
Water   |  fluidounce. 
Diluted  Alcohol   1 
Syrupy  Glucose   £  " 
Syrup,  enough  to  make   16  " 
Dissolve  the  iodide  of  potassium  in  one-half  (J)  fluidounce  of  water 
and  the  tartaric  acid  in  one-half  fluidounce  of  diluted  alcohol.  Mix 
the  two  solutions  in  a  vial,  cork  and  shake  it  well,  and  then  place  it  in 
ice-water  for  about  half  an  hour  ;  again  shake  it  thoroughly,  and  then 
pour  the  mixture  upon  a  small  white  filter,  and  filter  into  a  bottle  con- 
taining 13f  fluidounces  of  syrup  and  one-fourth  (J)  fluidounce  of 
syrupy  glucose.  When  the  liquid  has  run  through,  wash  the  vial  and 
filter  with  one-half  (J)  fluidounce  of  diluted  alcohol,  added  in  several 
portions.    Then  add  enough  syrup  to  make  sixteen  (1 6)  fluidounces. 
The  product  is  a  clear,  transparent,  almost  colorless  liquid,  odorless, 
