362  Syrup  of  Ferrous  Iodide.  {^m"Siu/,'i89h5arm" 
rows  of  two  or  three,  and  the  cells  are  shorter  and  broader  than  the 
crystal  cells,  though  they  are  not  usually  so  large  as  the  parenchyma 
cells  with  which  they  are  associated.  They  are  scattered  without 
apparent  order  through  the  inner  bark.  Besides  the  oleo-resin  cells 
proper,  just  described,  oleo-resin  occurs  in  many  cells  not  especially 
devoted  to  secretions.  This  is  particularly  true  of  the  cells  in  the 
older  portions  of  the  bark. 
DESCRIPTION  OF  FIGURES. 
Fig.  1. — Small  portion  of  cross-section  of  bark  of  Tsuga  Canadensis,  magni- 
fied about  50  diameters,  c,  c,  c,  secondary  cork  formation  ;  a,  dead  phloem 
tissues  rich  in  coloring,  resin  and  tannic  matters  ;  s,  s,  stone  cells  ;  m,  m, 
medullary  rays  ;  cr,  crystal  cell  ;  ca,  cambium. 
Fig.  2. — Small  portion  of  longitudinal -tangential  section  of  the  inner  bark  of 
Tsuga  Canadensis,  magnified  about  75  diameters,  a,  a,  medullary  rays,  the  cells 
containing  much  starch  ;  b,  b,  stone  cells  ;  e,  row  of  cells  containing  crystals 
of  calcium  oxalate  ;  s,  cell  coutaining  oleo-resinous  secretion. 
Fig.  J. — A  few  of  the  crystals  magnified  230  diameters. 
Fig.  4.. — Small  portion  of  cross-section  of  bark  of  Tsuga  Mertensiana,  magni- 
fied about  50  diameters,  c,  c,  c,  bands  of  secondary  cork  ;  a,  intervening  dead 
tissues  composed  of  sieve  and  parenchymatous  elements,  and  like  the  other 
species,  rich  in  tannic,  resinous  and  coloring  matters  ;  s,  s,  groups  of  stone 
cells  ;  m,  m,  relatively  large,  fusiform  medullary-ray  cells ;  b,  band  of 
large  parenchymatous  cells  ;  cr,  crystal  cell ;  ca,  cambium  cells. 
Fig.  5. — Small  portion  of  longitudinal-tangential  section  of  bark  of  Tsuga 
Mertensiana,  magnified  about  75  diameters,  s,  cluster  of  stone  cells ;  cr, 
crystals  of  calcium  oxalate  ;  m,  m,  medullary  rays  ;  r,  oleo-resin  cell. 
SYRUP  OF  FERROUS  IODIDE.  -  
By  Chari.es  F.  Carter,  Ph.G. 
Contribution  from  the  Chemical  Laboratory  of  the  Philadelphia  College  of 
Pharmac37.    No.  143. 
The  United  States  Pharmacopoeia  designates  syrup  of  ferrous 
iodide  as  "  a  syrupy  liquid,  containing  about  10  per  cent.,  by  weight, 
of  Ferrous  Iodide  [Fel2  =  308-94],  or  about  13-4  gm.  in  100  c.c." 
This  preparation  has  always  been  considered  as  tedious  to  make, 
and  also  as  difficult  to  maintain  in  a  perfect  state,  on  account  of  the 
unstable  character  of  the  ferrous  compound,  which  is  prone  to 
decompose  with  the  liberation  of  iodine.  To  guard  against  the 
presence  of  free  iodine,  the  Pharmacopoeia  orders  that,  to  be 
official,  a  syrup  should  not  show  a  blue  color  when  it  is  mixed  with 
a  small  quantity  of  starch  test  solution. 
