328  Solution  and  lincture  of  Ferric  Chloride.  {AmjJu°iyr;if£arm- 
percentage  of  ferric  chloride,  as  in  Table  I.  Compare  the  average 
of  the  two  columns  and  observe  that  the  specific  gravity  is  above  that 
required  by  the  U.  S.  P.,  whilst  the  percentage  of  ferric  chloride  is 
below.  Solutions  Nos.  9,  10  and  11  having  the  highest  specific 
gravity  are  almost  inversely  proportioned  in  value  of  ferric  chloride. 
Such  dissimilarities  may  be  due  to  various  causes.  The  specific 
gravity  is  dependent  upon  the  amount  of  ferric  chloride  present,  the 
quality  of  the  alcohol,  and  it  is  regretting  to  mention  that  some  of 
the  samples  are  largely  influenced  by  the  presence  of  water. 
By  a  simple  calculation  the  parts  by  weight  of  the  solution  used 
in  making  the  respective  tincture  by  the  retail  pharmacist  can  be 
ascertained  from  the  results  obtained  by  the  analyses. 
A  tincture  made  with  a  deficient  amount  of  solution,  yet  retaining 
its  specific  gravity,  or  as  in  many  instances  is  materially  increased, 
is  evidence  of  the  fact  that  water  has  been  added. 
It  may,  therefore,  be  assumed  that  all  tinctures  having  a  specific 
gravity  above  that  of  -980  and  a  percentage  of  ferric  chloride  below 
that  of  13-25,  contain  a  certain  amount  of  water  in  substitution  for 
alcohol.    Nos.  2,  9,  10  and  11  are  examples  of  this  class. 
Many  writers  claim  it  is  impossible  for  tinctures  to  be  devoid  of 
ferrous  salt ;  however,  as  stated  in  the  table,  reactions  were  obtained 
from  six  only. 
Some  of  the  tinctures  were  not  made  long  before  the  samples 
were  collected.  From  this  time  they  had  been  kept  in  the  dark 
until  the  tests  were  applied. 
The  gradual  decomposition  taking  place  is  accelerated  by  heat 
and  light  with  the  reduction  of  ferric  salt  into  ferrous.  Possibly  if 
the  tinctures  were  allowed  to  stand  a  considerable  length  of  time, 
and  exposed  to  heat  and  light,  they  would  afford  a  reaction  for  fer- 
rous salt.  Invariably  nitric  acid  was  found  to  be  present  in  the 
solutions,  sometimes  ferrous  chloride,  and  very  seldom  could  they 
be  secured  free  from  both  these  impurities.  The  presence  of  nitric 
acid  may  be  regarded  as  the  result  of  pure  carelessness. 
Laboratory  of  the  Maryland  College  of  Pharmacy, 
June,  1894. 
The  Scotch  Broom  is  a  useful  flowering  shrub  early  in  June.  When  planted 
on  high  well  drained  land  it  is  perfectly  hardy  near  Philadelphia,  although 
further  north  it  suffers  unless  carefully  protected  in  winter. 
