"""fIS^'i'sso''" • }  ^y^^f  of  Bromide  of  Zinc,  7  7 
Experiment  III.  1 00  grains  of  potassium  bromide  and  240  grains  of 
crystallized  sulphate  of  zinc.  The  same  process  as  11  was  followed. 
The  residue,  after  treatment  with  sulphhdyate  of  ammonium,  was  very 
minute — a  trace  of  potassium  salt. 
A  solution  of  bromide  of  zinc,  made  by  acting  with  bromine  upon 
the  metal,  was  filtered  through  paper  and  evaporated  to  dryness.  It 
gave  a  dark  grey  colored  mass,  whereas  a  portion  of  the  same  solution,, 
filtered  through  asbestos  and  evaporated,  gave  a  perfectly  white  mass. 
The  coloration  in  the  former  case  is  evidently  due  to  organic  matter, 
showing  the  analogy  of  the  bromide  with  chloride  of  zinc,  which  also 
dissolves  organic  matter,  showing  the  analogy  of  the  bromide  with 
chloride  of  xinc,  which  also  dissolves  organic  matter.  Even  the  alco- 
holic solution  of  bromide  of  zinc,  filtered  through  asbestos,  will  yield 
a  dark  colored  salt  on  evaporation. 
Perhaps  the  most  convenient  preparation  for  the  administration  of 
bromide  of  zinc  would  be  a  syrup  of  definite  strength.  A  syrup  con- 
taining 10  per  cent,  of  dry  bromide  of  zinc  was  made  by  using  the 
solution  from  experiment  III,  and  evaporating  the  alcohol.  The 
amount  of  dry  bromide  was  calculated,  and  found  to  be  92  grains. 
Water  was  added  to  make  the  whole  weigh  414  grains,  and  afterwards 
506  grains  of  sugar,  which  was  dissolved  without  the  aid  of  heat.  The 
proportions  used  are  as  follows : 
92  grains  ZnBr^,   .  .  .  .10  parts 
322  grains  water,  .  .  '35 
506  grains  sugar,    .  ,  .  '55 
920  grains.  100  parts. 
Formula  for  making  i,000  parts  of  Syrupus  Zinci  Bromidi. 
Take  of    Bromide  of  potassium,  .  .106  parts 
Crystallized  sulphate  of  zinc,  .  255 
Dissolve  the  salts  separately  in  the  least  quantity  of  water,  and  mix 
while  hot.  Allow  the  mixture  to  stand  until  cold,  then  add  twice  the 
bulk  of  alcohol;  stir  it  well  and  filter.  Evaporate  the  filtrate  until  the 
alcohol  is  gone,  then  add  enough  distilled  water  to  make  the  solution 
weigh  450  parts;  transfer  to  a  bottle  and  add  sugar,  550  parts.  Dis- 
solve without  heat. 
The  syrup  is  transparent  and  nearly  colorless.  It  is  inodorous  and 
has  an  astringent  and  somewhat  metallic  taste.  It  can  be  given  in 
combination  with  most  tinctures  and  syrups.  An  agreeable  prepara- 
tion is  made  by  combining  it  with  orange-flower  water. 
