168  Precautions  in  Dispensing  Poisons.  {k\v™Xmt™' 
4  cc,  in  proportion  as  the  iodide  has  been  replaced  by  bromide  of 
potassium. 
To  prove  the  presence  of  bromine  in  the  liquid  filtered  from  the 
mercuric  iodide,  it  is  evaporated  to  about  8  grms.;  after  cooling  it  is 
put  into  a  test-tube  and  boiled  with  a  few  drops  of  perchloride  of  iron 
until  it  ceases  to  disengage  vapors  of  iodine,  which  is  recognized  by 
the  vapors  being  without  effect  upon  starch  paper.  The  cooled  liquid 
is  'filtered  and  then,  in  a  test-tube,  agitated  repeatedly  with  small 
quantities  of  chlorine  water  and  bisulphide  of  carbon  until  the  latter 
ceases  to  become  colored  from  the  dissolved  bromine. 
The  presence  of  bromine  may  also  be  demonstrated  by  agitating 
the  concentrated  filtrate  from  the  mercuric  iodide  obtained  as  above 
with  three  fresh  portions  of  ether,  which  dissolves  from  the  aqueous 
solution  the  excess  of  mercuric  chloride,  the  double  iodide  of  mercury 
and  potassium,  and  traces  of  the  bromide.  If  the  operation  has  been 
well  performed,  the  liquid  contains  only  bromide  and  chloride  of 
potassium,  from  the  former  of  which  the  bromine  is  easily  separated 
by  chlorine  water  and  bisulphide  of  carbon. — Journ.  de  JPharm.  et  de 
(Mm.,  1872,  Fevr.,  103—105. 
PRECAUTIONS  IN  DISPENSING  POISONS. 
By  William  C.  Bakes,  of  Philadelphia. 
Query  23. — What  are  the  best  containers,  or  what  other  precautions  can  be 
devised  for  poisonous  drugs,  to  lessen  their  liability  to  mistakes  in  dispensing 
or  handling  them  ? 
This  is  a  topic  upon  which  much  might  be  written,  and  even  then 
the  conclusions  arrived  at  might  not  seem  satisfactory.  It  must  be 
conceded  that  the  ordinary  methods  of  keeping  and  dispensing  poisons 
are  liable  to  much  criticism.  In  these  times  when  there  is  so  much 
free  trade  in  medicine ;  when  any  man,  however  ignorant  and  un- 
skilled, is  privileged  to  practice  medicine,  or  deal  in  drugs,  it  is  of 
the  greatest  importance  that  some  safeguards  should  be  thrown  around 
the  storage  as  well  as  dispensing  of  poisons.  In  some  States,  laws 
have  been  enacted  regulating  the  sale  of  poisons.  Some  years  since, 
the  Legislature  of  Pennsylvania  passed  a  law  requiring  that  all  par- 
ties selling  poisons  should  keep  a  record  of  the  date  of  sale,  name 
and  address  of  each  purchaser,  with  the  quantity  of  the  article  sold. 
This  law  is  scarcely  regarded,  and  the  existence  of  it  may  not  be 
