DIALYSIS  APPLIED  TO  INVESTIGATION  OP  ALKALOIDS.  415 
remaining  in  the  dialyser ;  it  volatilizes,  leaving  no  residue, 
all  the  digitaline  having  passed  into  the  dialysed  liquid. 
2.  Dialysis  of  Urine,  containing  1  gr.  01  of  Digitaline  
Into  45  cubic  centimetres  of  fresh  normal  urine  pour  2  cubic 
centimetres  of  a  solution  containing  0  gr.  50  of  digitaline  to 
100  centimetres  cube  of  water  ;  after  eighteen  hours  suspend 
the  dialysis  and  evaporate  to  dryness  the  liquid  in  the  outer  ves- 
sel (about  300  cubic  centimetres).  Extract  the  almost  color- 
less residue  by  alcohol  ;  and  the  alcoholic  solution,  evaporated 
to  dryness,  shows  all  the  characteristics  of  digitaline  with  as 
much  clearness  as  the  residue  of  2  cubic  centimetres  of  the 
normal  solution  of  digitaline.  Evaporate  separately  the  con- 
tents of  the  dialyser,  and  the  residue  will  be  brown  ;  then  ex- 
tract by  alcohol  of  95°,  and  the  greenish  solution  thus  obtained 
will  give  all  the  reactions  indicating  the  presence  of  traces  of 
digitaline.    The  dialysis  then  was  not  complete. 
8.  Dialysis  of  Morphine,  Brucine  and  Digitaline  mixed  with 
Animal  matters. — Take  the  stomach  and  intestines  of  a  dog  (some 
hours  after  death),  macerate  them  in  water  at  25°  or  30°  for 
about  two  hours ;  filter  the  yellowish,  strongly-smelling  liquid 
through  canvas.  Divide  it  into  four  parts,  each  of  250  cubic  cen- 
timetres ;  to  the  first  add  0  gr.  01  of  digitaline  ;  to  the  second, 
0  gr.  02  brucine ;  to  the  third,  0  gr.  02  of  hydrochlorate  of 
morphine ;  leave  the  fourth  intact  ;  dialyse  these  four  liquids 
separately.  After  twenty-four  hours  carefully  evaporate  the 
liquids  contained  in  the  outer  vessels  ;  recover  each  of  the 
residues  by  alcohol,  to  separate  the  mineral  salts  (salts  of  soda, 
lime,  &c.)  which  have  been  dialysed.  The  ordinary  reagents 
of  brucine  (nitric  acid)  and  of  morphine  (nitric  acid,  perchlo- 
ride  of  iron)  clearly  show  the  presence  of  these  alkaloids  in 
the  residues  of  the  alcoholic  liquids.  Digitaline  is  found 
equally  in  the  water  of  the  first  vessel.  Divide  the  residue  of 
the  evaporation  of  that  portion  of  the  liquid  to  which  no  vege- 
table alkali  was  added  into  several  parts,  and  test  it  with  the 
reagents  used  to  discover  brucine,  morphine,  and  digitaline. 
This  experiment  is  merely  intended  to  show  that  the  animal 
matters,  to  which  the  poisonous  substances  are  added,  do  not  by 
themselves,  give  reagents,  colorations  which  might  lead  to  error. 
The  result  of  this  test  leaves  no  doubt  as  to  the  value  of 
dialysis  applied  to  researches  of  this  kind. 
