^m-^t/Jm^m-} Dialysis  by  Means  of  Calcium  Sulphate.  427 
liquid  contained  in  the  dialyzator  is  not  precipitated  by  the  general 
reagents  for  alkaloids,  the  process  is  discontinued. 
"  The  hydrated  absorbent  is  powdered  and  by  means  of  lixiviation 
or  maceration  with  concentrated  alcohol  the  organic  salts  are 
separated. 
"  Proceeding  in  this  way  an  almost  pure  alcoholic  solution  of  the 
alkaloidal  salt  is  obtained,  not  containing  extractive,  coloring  or 
resinous  matter.  For  extracting  the  organic  base  it  is  sufficient  to 
separate  the  alcohol  by  distillation  or  evaporation,  to  dissolve  the 
residue  in  water  and  precipitate  by  means  of  an  alkali  or  alkaline 
carbonate." 
He  considers  the  process  may  be  applicable  to  the  separation  of 
glucosides,  to  the  concentration  of  extractive  liquids,  to  the  con- 
centration of  extracts  which  owe  their  activity  to  colloid  substances 
and  to  toxicological  investigations. 
My  oivn  experiments  on  the  above  methods. — The  following  are 
some  of  the  results  of  my  own  experiments  which  I  made  three 
times. 
Ten  grams  of  powdered  opium  were  macerated  for  24  hours  in 
water  acidulated  with  -5  per  cent,  of  tartaric  acid,  after  this  time  the 
liquid  was  filtered  and  the  residue  washed  with  water  until  200  cc. 
of  the  liquid  were  obtained.  I  started  the  dialyzation,  using  two 
dialyzators  made  of  parchment  paper,  folded  like  filters  and  fastened 
to  wooden  frames.  I  divided  the  liquid  between  the  two  and  sur- 
rounded them  with  recently- calcined  sulphate  of  calcium.  After  24, 
hours  the  level  of  the  liquid  in  the  dialyzators  had  lowered,  and 
with  the  object  of  putting  the  septum  in  contact  with  a  fresh  por- 
tion of  the  absorbent,  I  removed,  carefully,  the  filter  and  scraped 
the  hydrated  part  off  and  removed  it  as  completely  as  possible  from 
the  non-hydrated  portion,  using  the  latter  as  an  absorbent  for  a 
continuation  of  the  process.  The  operation  was  then  continued  for 
four  days,  at  the  end  of  which  time  one  of  the  parchments  com- 
menced to  decompose  and  the  liquid  was  transferred  to  the  other, 
at  the  end  of  two  more  days  the  2d  parchment  commenced  to 
decompose  and  the  operation  was  stopped. 
After  powdering  the  hydrated  sulphate  it  was  packed  in  a  perco- 
lator and  treated  with  1,200  cc.  of  95  per  cent,  alcohol,  employing 
about  5  days  in  the  percolation,  which  was  stopped  when  the  per- 
colate ceased  to  give  any  reaction  for  alkaloids. 
