Am.  Jour.  Pharm  ) 
May,  1882.  f 
Hyrup  of  Hydriodic  Acid. 
239 
In  using  this  apparatus  for  preparing  fluid  extracts  only  one  pint  of 
menstruum  for  every  sixteen  ounces  of  the  material  is  employed^  and 
after  the  liquid  has  ceased  to  run  into  the  receiver,  more  menstruum 
is  added,  just  sufficient  to  produce  a  pint  of  the  finished  product.  No 
evaporation  of  any  portion  of  the  tincture  is  required  as  in  the  officinal 
process. 
By  means  of  suitable  iron  pipes  any  number  of  percolators  and 
receivers  may  be  connected  with  a  stationary  air-pump,  and  after  clos- 
ing the  stop-cocks  of  the  others  the  air  in  any  one  vessel  may  be  rare- 
fied or  compressed  at  pleasure. 
SYRUP  OF  HYDRIODIC  ACID. 
By  W.  Gilmour. 
An  American  preparation  of  hydriodic  acid  in  the  form  of  a  syrup 
has  lately  been  brought  under  the  notice  of  medical  men  and  phar- 
macists in  this  country,  with  the  reconimendation  that  the  acid  "  is 
perfectly  protected  against  decomposition — a  result  never  before 
attained.'^  Into  the  composition  of  this  particular  syrup,  or  its  pre- 
servative medium,  I  will  not  at  present  enter,  but  I  wish  to  point  out 
that  the  statement  here  made,  as  also  that  in  the  recommendatory 
advertisement,  that  simple  mixtures  of  hydriodic  acid  and  syrup  do 
not  keep,''  are  only  partially  correct. 
Nearly  thirty  years  ago,  when  this  preparation  was  first  introduced, 
Mr.  Murdoch,  of  Glasgow,  showed  that  a  syrup  of  this  acid  could  be 
kept  with  ordinary  care  for  an  indefinite  period.  This  is  my  own 
experience  also.  With  attention  to  the  conditions  afterwards  to  be 
referred  to,  there  is  less  trouble  from  decomposition  with  a  syrup  of 
this  acid  than  there  is  with  a  syrup  of  any  of  tlie  ordinary  ferrous 
preparations. 
It  will  probably  be  remembered  by  many  that  Dr.  Buchanan,  who 
was  the  first  to  bring  this  acid  prominently  under  medical  notice  as  a 
therapeutic  agent,  recommended  that  it  should  be  prepared  extempora- 
neously by  double  decomposition  of  concentrated  solutions  of  iodide 
of  potassium  and  tartaric  acid.  When  prepared  in  this  way  the  result- 
ing liquid  is  of  a  bright  yellow  color,  deepening  quickly  into  a  darker 
red,  and  giving  abundant  indications  of  the  presence  of  free  iodine 
within  a  very  short  time  of  its  preparation.    Mr.  Murdoch  attributed 
