PREPARATIONS  OP  THE  U.  S.  PHARMACOPEIA,  1860.  327 
It  is  quite  necessary  to  evaporate  the  solution  at  a  moderate 
temperature,  and  it  is  safest  to  protect  the  surface  of  the  capsule 
above  the  evaporating  solution  from  direct  heat,  lest  a  part  of 
the  salt  adhering  to  it  be  decomposed.  The  entire  solubility  of 
the  chloride  in  cold  water  is  a  test  of  its  correct  preparation  as 
regards  heat. 
Chloride  of  iron  is  most  convenient  for  making  the  several 
solutions  and  the  syrup  of  chloride  of  iron.  The  latter  is  a  pre- 
paration of  French  origin,  and  is  obtained  by  dissolving  a  drachm 
of  the  salt  in  twenty-three  drachms  of  simple  syrup.  The  British 
Pharmacopoeia  "solution  of  perchloride  of  iron"  is  a  dense 
solution  of  sesquichloride  of  iron  mixed  with  some  protochloride 
and  subsesquichloride,  containing  theoretically  87 J  grains  of 
metallic  iron  to  the  fluid  ounce, — equal  to  421  grains  of  the  ses- 
quichloride, but  practically  it  is  less  concentrated.  When  pre- 
scribed, it  may  be  imitated  by  taking  7  drachms  (420  grains)  of 
the  crystalline  chloride,  put  it  in  a  graduated  measure,  and  add 
water,  carefully,  stirring  with  a  glass  rod,  until  it  measures  a 
fluid  ounce.  About  246  minims  of  water  are  required;  of  course 
it  is  more  economical  to  prepare  the  solution  directly  by  the 
British  process,  if  needed,  in  sufficient  quantity. 
Tinctura  Ferri  Chloridi. — The  formula  now  in  the  Pharma- 
copoeia is  that  recommended  by  Dr.  Squibb.  (See  Amer.  Journ. 
Pharm.,  vol.  xxix.  p.  289.)  The  solution  of  chloride  of  iron  is  ob- 
tained as  has  been  spoken  of  under  chloride  of  iron.  An  excess 
of  a  fluid  ounee  of  muriatic  acid  is  used  in  this  case,  however, 
intended  partially  for  its  therapeutic  qualities,  and  partially  to 
avoid  the  presence  of  subchloride.  When  a  deficiency  of  nitric 
acid  is  used,  a  portion  of  protochloride  remains  unconverted. 
This  by  the  gradual  action  of  the  air  is  changed,  and  affords  a 
deposit.  When  well  made,  this  tincture  keeps  without  deposition 
of  subchloride. 
Pilulce  Ferri  Carbonatis.  Vallefs  Mass. — This  formula  is  pre- 
cisely as  it  was  in  1850.  Various  pharmaceutists  have  tried  to 
vary  the  proportion  of  sugar  and  honey  so  as  to  get  a  less  hy- 
groscopic mass.  The  prevailing  opinion  is  in  favor  of  reversing 
the  proportions,  using  two  troy  ounces  of  honey  to  three  troy 
