PHARMACEUTICAL  GLEANINGS. 
iron,  a  preparation  exceedingly  liable  to  undergo  change  of  color 
and  partial  decomposition,  without  proper  care,  may  not  be  out 
of  place  here,  as  there  is  an  error  both  in  books,  and  in  the 
minds  of  many,  if  not  most  druggists,  in  relation  to  the  causes  pro- 
ductive of  these  changes.  It  is  altogether  wrong  to  attribute  these 
effects  to  exposure  to  light,  as  specimens  in  my  possession  which 
have  been  exposed  to  the  direct  rays  of  the  sun  for  months,  with 
the  effect  of  only  lightening  the  color,  will  sufficiently  prove. 
The  causes  of  this  alteration  must  then  be  looked  for  elsewhere. 
The  action  of  the  air  upon  this  preparation  has  not  escaped  atten- 
tion altogether,  but  has  not  been  considered  the  sole  cause  which  I 
believe  it  to  be,  and  that  the  superior  affinity  of  the  oxygen  of  the 
air  for  the  iron  on  the  iodine,  thereby  setting  the  latter  free,  is 
a  sufficient  cause  for  the  discoloration.  A  simple  change  of  co- 
lor, from  a  light  green  to  a  reddish  hue,  need  not  condemn  the 
article.  So  long  as  there  is  no  deposit,  and  the  preparation  quite 
transparent,  it  may  be  considered  good,  although  not  so  nice 
looking.  This  statement  may  perhaps  obviate  the  troublesome 
plan  adopted  by  some  very  careful  druggists,  of  covering  with  dark 
paper,  or  painting  the  vials  in  which  the  syrup  is  dispensed. 
PHARMACEUTICAL  GLEANINGS. 
New  process  for  coating  Pills. — M.  Calloud,  (de  ChambeYy)  in 
Journal  de  P  liar  made,  xxiii.  301,  treats  of  the  subject  of  envel- 
oping medicinal  substances  in  a  covering  to  prevent  unpleasant 
taste.  After  having  tried  gum,  starch  and  sugar  without  satis- 
faction, owing  to  the  hygroscopic  tendency  of  the  sugar  and  gum 
in  moist  air  or  with  a  moist  mass,  and  their  tendency  to  crack 
when  very  dry,  he  had  recourse  to  the  dried  mucilage  of  flax- 
seed prepared  with  sugar,  with  success. 
The  following  is  his  method  : 
Take  of  Flaxseed,        one  part. 
White  sugar,    three  parts. 
Spring  water,  a  sufficient  quantity. 
A  thick  mucilage  is  obtained  by  carefully  boiling  the  seeds,  the 
sugar  is  added,  and  the  whole  of  the  moisture  evaporated  by  care- 
ful desiccation. 
This  mixture  is  but  very  slightly  hygroscopic,  may  be  reduced 
