Am.  Jour.  Pharm.  i 
February,  1895.  J 
Pharmaceutical  Notes. 
85 
pounds  are  productive  of  color  changes,  which  are  at  times  difficult 
of  explanation. 
These  may  be  produced  by  impure  articles,  in  this  instance  the 
iron-contaminated  glycerin. 
In  a  number  of  instances,  where  glycerin  was  kept  in  the  con- 
tainers mentioned,  such  reactions  were  produced  and  found  at  times 
to  be  the  source  of  considerable  trouble. 
It  is  hardly  necessary  to  mention  the  various  iron  reactions,  as 
they  aie  found  in  every  chemical  text-book. 
But  to  the  pharmacist  a  few  are  of  importance,  as  they  are  liable 
to  occur  at  the  dispensing  counter,  when  the  presence  of  a  trace  of 
iron  in  commercial  glycerin  is  not  suspected. 
PREPARATIONS  OF  TANNIN  AND  GALLIC  ACID. 
In  the  popular  glycerite  of  tannin  we  find  the  preparation  not 
unfrequently  to  turn  a  blackish-brown  color,  no  matter  how  careful 
we  may  be  in  the  handling  of  our  working  utensils. 
Examination  of  the  glycerin,  which  appears  to  contain  the  metal 
in  the  ferric  form,  will  reveal  the  cause  of  the  coloration. 
Extemporaneously  prepared  nipple  washes,  containing  tannin,  or 
similar  preparations,  are  apt  to  show  the  same  effect,  as  will  also 
preparations  containing  tannin-like  principles. 
In  connection  with  this,  attention  may  be  called  to  the  presence 
of  tannin  in  commercial  alcohol. 
The  average  pharmacist  accepts  this  most  important  solvent  from 
his  dealer  without  even  attempting  a  superficial  examination  as  to 
its  purity,  and  does  not  recognize  the  importance  of  the  same  until 
he  finds  color  changes  in  delicate  preparations. 
Elixirs  containing  scaled  iron  salts  often  show  this  result, 
and  the  question  :  Why  does  elixir  iron,  quinine  and  strychnine 
turn  dark  after  standing  a  short  time?  may  find  partly  an  explana- 
tion in  the  tannin-containing  alcohol  of  commerce. 
Such  alcohol,  or  preparations  made  therefrom,  when  mixed  with 
glycerin  kept  in  tinned  iron  cans,  will  show  the  same  effect. 
EFFECT  UPON  PHENOL  COMPOUNDS. 
The  delicacy  of  the  iron  reaction  with  phenol  compounds  is  well 
known. 
Carbolic  acid  is  frequently  prescribed  in  a  mixture  with  glycerin 
