270  Gleanings  from  the  Foreign  Journals.  {Am-j{Ter;x87h6arm- 
The  above  formula,  although  not  containing  the  same  amount  of 
prepared  chalk,  contains  the  metallic  mercury  in  the  same  proportion 
(3  in  8)  as  called  for  in  the  "  U.  S.  Pharmacopoeia,"  and  I  think  is 
more  efficacious  as  a  remedy,  as  the  mercury  is  more  thoroughly 
divided. 
In  the  above,  I  state  the  result  of  my  manipulations  with  sugar  of 
milk  and  those  substances  that  are  required  to  be  in  a  very  minute 
state  of  division  ;  and  I  feel  confident  that  those  who  will  employ  this 
substance  in  the  manner  and  for  the  purpose  I  have  described,  cannot 
fail  to  acknowledge  that  sugar  of  milk  is  preferable  to  all  other  sub- 
stances. Being  perfectly  harmless,  of  a  hard,  gritty  nature,  and  chemi- 
cally a  perfectly  definite  material,  I  feel  certain  that  it  will  supercede  the 
old  practice  of  employing  heat  in  powdering  the  gum  resins.  More- 
over, in  dispensing  emulsions,  sugar  of  milk  materially  assists  in  the 
formation  of  a  perfect  emulsion,  by  reason  of  the  minute  state  of  di- 
vision of  the  gum  resin,  induced  by  the  trituration  of  sugar  of  milk 
with  the  drug. 
GLEANINGS  FROM  THE  FOREIGN  JOURNALS. 
BY    THE  EDITOR. 
The  Decomposition  of  White  Precipitate  by  Iodine,  Chlorine  and  Bromine. 
— V.  Schwarzenbach  has  observed  that  iodine  may  be  triturated  with 
white  precipitate,  or  heated  with  it  in  a  crucible,  without  any  other 
result  being  observed,  especially  in  the  latter  case,  than  the  formation 
of  beautiful  red  crystals  of  mercuric  iodide.  But,  if  alcohol  be  added 
to  the  mixture,  in  an  open  vessel,  after  some  time  (about  35  minutes) 
a  smart  explosion  takes  place,  which  inevitably  destroys  the  vessel,  if 
it  be  of  glass,  but  only  to  the  exact  height  reached  by  the  surface  of 
the  liquid.  Up  to  the  time  of  explosion  no  rise  in  temperature  was 
observed,  and  the  inserted  thermometer  remained  uninjured  when  the 
vessel  was  destroyed.  In  direct  sunlight,  the  explosion  followed  more 
rapidly,  frequently  in  9  or  10  minutes.  Among  the  products,  scat- 
tered by  the  explosion,  were  red  mercuric  iodide,  and  strongly  detonat- 
ing particles  of  nitrogen  iodide  of  considerable  size  ;  the  gas  evolved 
was  identified  as  nitrogen.  If  chloroform  or  amylic  alcohol  are  used, 
instead  of  ethylic  alcohol,  and  the  iodine  is  increased  .to  six  atoms 
for  two  molecules  of  white  precipitate,  strong  detonations  occur  in 
the  liquid. 
