%ecTiP8?3RW  }       Action  of  Water  upon  Opium.  543 
solution  of  extract  of  opium,  as  shown  by  the  following  experi- 
ments : — 
(1)  120  grams  of  extract  of  opium  was  divided  into  two  equal 
parts  ;  one  half  was  treated  with  120  grams  of  distilled  water  at  15° 
•C,  the  other  half  with  250  grams  of  water  at  the  same  temperature. 
At  the  end  of  six  hours,  assisted  by  agitation,  solution  was  complete 
in  both  liquids,  and  they  were  filtered  through  paper.  The  first  only 
sleft  a  few  bubbles  of  blackish  matter  ;  the  second  abandoned  six  grams 
of  oleo-resin. 
(2)  The  first  solution  was  then  evaporated  to  dryness  and  the 
product  divided  into  two  parts  ;  one  was  put  into  a  small  quantity  of 
water  (about  twice  its  own  weight),  the  other  into  1000  grams.  After 
twenty-four  hours  the  concentrated  liquor  was  quite  limpid  and  with- 
out deposit,  but  the  dilute  liquor  had  deposited^  a  considerable 
residue. 
(3)  30  grams  of  extract  was  dissolved  in  water,  under  the  conditions 
prescribed  in  the  Codex  (ten  times  its  weight  of  water  at  15°  C). 
The  solution  was  at  first  muddy,  a  black  granular  precipitate  covered 
the  bottom  of  the  vessel ;  but  upon  evaporation  in  a  water-bath  the 
extract  again  became  homogeneous,  and  afterwards  dissolved  in  30 
grams  without  any  deposit.  In  its  turn,  this  solution  threw  down  a 
precipitate  when  double  its  own  volume  (60  grams)  of  water  was 
added,  and  the  precipitate  was  augmented  commensurately  with  the 
addition  of  more  water.  Afterwards  concentration  reproduced  a  nor- 
mal extract,  soluble  without  residue. 
(4)  The  quantity  of  water  employed  gave  rise  to  a  regular  pro- 
gression in  the  phenomena  of  solution  and  precipitation.  If,  for 
example,  five  grams  of  extract  of  opium  were  put  in  ten  grams  of 
distilled  water,  the  portion  which  was  first  dissolved  left  in  suspension 
a  granular  deposit.  In  proportion  as  the  liquid  became  saturated  this 
deposit  was  effaced,  until  at  last  no  more  remained  undissolved.  The 
maroon  black  liquid,  a  layer  of  four  centimetres  of  which  was  imper- 
meable by  sunlight,  did  not  require  filtering ;  if  it  were  sometimes 
scarcely  clear  yet  it  did  not  deposit.  With  five  grams  more  water  a 
turbidity  was  manifested  which  was  not  completely  removed  by  shak- 
ing. At  the  maximum  of  20  grams  of  water  the  deposit  commenced  ; 
towards  30  grams,  and  after  standing  for  an  hour,  the  deposit  was 
nearly  doubled ;  at  50  grams  (ten  times  the  weight  of  the  extract) 
it  ceased,  and  the  liquid  was  no  longer  troubled  by  fresh  additions  of 
water. 
