^"'june'isso^''"' }  Gleanifigs  from  the  German  Journals,  323 
the  best  tooth  powder  and  alcohol  the  best  addition  to  a  mouth  wash, 
and  states  that  both  may  be  perfumed  if  desired. — Ihid.^  March  25, 
1880,  p.  108. 
"  Succus  Citri  Depuratus  "  is  the  name  suggested  by  Hager  for 
the  purified  lemon  juice  prepared  by  Fleischer  &  Co.,  who,  by  intro- 
ducing it  into  the  German  market,  according  to  Hager,  supplied  a  long- 
felt  demand  for  a  substitute  for  the  commercial,  cloudy,  Italian  juice, 
which  almost  always  contains  acetic  acid.  Fleischer's  German  juice  is 
prepared  by  purifying  and  clarifying  fresh  lemon  juice,  is  either  color- 
less or  slightly  yellowish,  perfectly  clear,  contains  9*3  to  9*4  per  cent, 
acid,  and  keeps  for  weeks  in  the  cold  season  of  the  year,  even  in  par- 
tially filled  bottles,  and  probably  equally  as  long  in  the  hot  season  if 
kept  in  full  and  well-corked  bottles. — Ihid.^  p.  105. 
Preparation  of  Potassium  Cantharidate  and  Cantharidin  by- 
Dialysis. — E.  Dieterich  recommends  digesting  for  5  hours,  and  boil- 
ing slightly  for  15  minutes,  1,000  grams  of  coarsely-powdered  canthar- 
ides,  50  grams  potassium  hydrate,  and  6,000  grams  of  water.  The 
cooled  liquid  is  strained  and  expressed,  and  the  residue  again  treated  as 
before,  adding  but  20  grams  potassium  hydrate.  The  liquid  is  filtered 
and  the  filtrate  transferred  to  three  dialyzers,  about  60  cm.  in  diameter, 
which  are  suspended  in  correspondingly  large,  shallow,  porcelain-lined, 
iron  dishes.  In  these  dialyzers  the  filtrate  is  digested  for  5  to  6  days, 
the  water  being  replaced  as  it  evaporates.  After  neutralizing  the 
dialyzed  brownish  liquid  with  dilute  sulphuric  acid,  powdered  charcoal 
is  added,  the  whole  evaporated  to  dryness,  the  dry  residue  mixed  with 
a  little  barium  carbonate,  and  then  boiled  with  acetic  ether ;  the  etherial 
liquid  is  distilled,  the  remaining  cantharidin  washed  with  alcohol  and 
recrystallized  from  acetic  ether,  when  it  is  obtained  in  brilliant  white 
crystals.  Thus,  the  author  obtained  a  yield  never  below  2'8o  grams, 
while  the  usual  method  never  yields  over  2*30  gram. — Ib'id.^  March  11, 
1880,  p.  87. 
Detection  of  Potassium  Iodide  in  Potassium  Bromide. — Hager 
recommends  powdering  a  number  of  crystals,  dissolving  O'l  gram  of 
this  powder  in  10  or  12  cc.  of  10  per  cent,  ammonia  water,  adding  i 
drop  of  silver  nitrate  solution,  and  shaking,  when  a  clear  solution  will  be 
obtained,  unless  iodide  of  silver  is  present,  a  small  percentage  of  which 
will  render  the  liquid  decidedly  cloudy.  This  test  is  sufficiently  accurate 
for  indicating  the  presence  of  an  objectionable  percentage  of  potassium 
iodide,  but  will  not  answer  for  detecting  very  minute  traces. 
