Amjune?i908arm* }     Chemical  Examination  of  Ipomcea  Purpurea.  277 
added  from  time  to  time  in  order  to  maintain  alkalinity.  This 
treatment  was  continued  until,  on  testing  a  small  portion  of  the 
liquid  with  water,  no  precipitate  was  produced,  a  condition  which 
was  never  attained  in  less  than  twelve  hours.  The  liquid  was  then 
diluted  with  a  little  water,  filtered,  and  the  alcohol  removed,  after 
which  it  was  deprived  of  the  excess  of  barium  by  means  of  carbon 
dioxide  and  filtering.  The  barium,  which  still  remained  in  the  fil- 
trate in  combination  with  the  acids  formed  from  the  resin,  was  exactly 
precipitated  by  sulphuric  acid,  when,  after  removing  the  barium 
sulphate,  a  clear,  lemon-yellow  liquid  was  obtained.  This  liquid 
was  subjected  to  distillation  with  steam  in  order  to  remove  any  vola- 
tile acids  present.  The  distillate,  which  contained  no  oily  drops, 
'was  extracted  with  ether.  The  ethereal  liquid  was  shaken  with  a 
solution  of  sodium  carbonate,  washed  with  water,  dried  with  calcium 
chloride,  and  the  ether  removed,  when  a  very  small  amount  of  an 
oily  residue  was  obtained,  which  possessed  a  somewhat  disagreeable 
odor.  The  sodium  carbonate  liquid  and  washings  were  then  acidi- 
fied and  extracted  with  ether,  the  ethereal  liquid  being  dried  with 
calcium  chloride  and  the  ether  removed,  when  10  grammes  of  a 
colorless  acid  were  obtained,  thus  representing  5  per  cent,  of  the 
weight  of  resin  originally  employed.  This  acid  was  distilled  under 
the  ordinary  pressure,  when  it  passed  over  almost  completely 
between  174  and  1760  C.  as  a  colorless  liquid,  having  an  odor 
resembling  that  of  valeric  acid.  On  analysis  it  gave  the  following 
results : 
01274  gave  0  2760  C02  and  o-i  132  H20.    C  —  59-1  ;  H  =  9  9 
0-1436  gave  0-3090  C02  and  o  1240  H2C    0  =  58-7;  H  =  9-6 
0-1428  gave  0-3082  C02  and  01256  H,0.    0=589;  H  =  9  8 
C5H10O2  requires  C  =  58  8  ;  H  =  9  8  per  cent. 
The  silver  salt  of  the  acid  was  also  prepared  and  analyzed. 
0  2240  gave,  on  ignition,  01 156  Ag.    Ag  =  51-6. 
C5H902  Ag  requires  Ag  =  51-7  per  cent. 
The  density  of  the  acid  was  0-9471  at  16-5°  C.  It  was  optically 
active,  and  a  determination  of  its  specific  rotatory  power  gave  the 
following  result : 
aD  in  a  25  mm.  tube  at  16-5°  C.  =  -f  4°  15',  whence  [«]D  -f  17-95°. 
