174 
Opuntia  Vulgaris,  Mill. 
f  Am.  Jour.  Priarm. 
I      April,  1896. 
cate  the  presence  of  glucosides.  Some  of  the  acidulated  solution 
was  agitated  with  petroleum  ether,  ether  and  chloroform  in  succes- 
sion, and  subsequently  rendered  alkaline  by  the  addition  of  ammo- 
nium hydrate,  and  again  agitated  with  more  of  the  same  solvents  in 
the  same  order ;  but,  upon  evaporation  of  the  solvents,  there  was 
nothing  obtained  to  indicate  either  alkaloids  or  glucosides.  Nor 
could  these  principles  be  detected  in  200  grammes  of  the  stem  which 
were  examined  in  the  same  manner. 
Hot  alcohol  was  poured  on  the  filter  containing  that  part  of  the 
ether  extract  which  was  insoluble  in  acidulated  water.  This  solvent 
dissolved  about  one-half  of  the  filter's  contents.  The  alcoholic 
solution  gave,  with  ferric  chloride,  an  olive-green  precipitate,  and 
with  alcoholic  solution  of  lead  acetate  a  yellowish-brown  precipi- 
tate. When  some  of  the  alcoholic  solution  was  poured  into  water 
a  turbidity  was  produced.  The  remaining  fourth  of  the  ether 
extract,  which  was  not  dissolved  by  either  acidulated  water  or  hot 
alcohol,  was  found  to  be  soluble  in  an  aqueous  solution  of  potassium 
hydrate  ;  and  from  its  solution  in  that  liquid  the  addition  of  diluted 
sulphuric  acid  in  excess  caused  a  precipitate  of  brownish-black  sub- 
stance. 
Absolute  alcohol  dissolved  10-64  Per  cent,  of  the  weight  of  the 
powdered  fruit.  The  extract  was  of  a  blackish-red  color,  with  a 
tinge  of  purple.  It  had  an  odor  like  that  of  prunes.  It  required 
prolonged  drying  at  no°  C.  before  a  constant  weight  was  reached, 
and  when  this  had  been  attained  the  extract  was  still  of  a  semi- 
solid consistence.  The  process  of  drying  did  not  affect  the  color 
or  odor. 
The  extract  was  treated  with  water  and  the  insoluble  part  filtered 
off.  The  filtrate  had  an  acid  reaction.  With  lead  acetate  it  gave  a 
whitish  precipitate,  while  with  ferric  chloride  but  little  change  was 
observed,  thus  showing  the  absence  of  tannin  from  this  extract. 
The  tests  for  alkaloids  and  glucosides  were  attended  with  negative 
results. 
To  estimate  the  sugar  in  this  and  the  other  extracts,  a  quantity 
of  the  water  solution  of  the  extract  was  completely  precipitated 
with  lead  acetate  for  the  purpose  of  removing  extractive  matter, 
which  otherwise  might  have  interfered  with  the  accuracy  of  the 
results.  The  mixture  was  filtered  and  the  precipitate  washed.  The 
washings  were  added  to  the  filtrate,  and  the  latter  saturated  with 
